BR112014006185B1 - Method and apparatus for decoding video data, method and apparatus for encoding video data, and computer readable memory - Google Patents

Abstract

DETERMINATION OF MOTION VECTOR FOR VIDEO ENCODING For each prediction unit (PU) that belongs to an encoding unit (CU), a video encoder generates a candidate list. The video encoder generates the candidate list such that each candidate in the candidate list that is generated based on motion information from at least one other PU is generated without using motion information from any of the PUs belonging to the CU. After generating the candidate list for a PU, the video encoder generates a predictive video block for the PU based on one or more reference blocks indicated by motion information from the PU. PU movement information is determinable based on movement information indicated by a candidate selected from the candidate list for the PU.

Description

[0001] This application claims the benefit of US Provisional Application No. 61/535,964 filed September 17, 2011, US Provisional Application No. 61/564,764, filed November 29, 2011, and US provisional order no. 61/564,799, filed November 29, 2011, the entirety of which is incorporated herein by reference.

technical field

[0002] The present disclosure relates to video encoding and, more particularly, to inter-frame prediction of video data.

background

[0003] Digital video capabilities can be embedded in a wide range of devices, including digital televisions, digital direct broadcast systems, wireless broadcast systems, personal digital assistants (PDAs), laptop or desktop computers, digital cameras, recording devices, digital media players, video game devices, video game consoles, cellular or satellite radio telephones, video teleconferencing devices, and the like. Digital video devices implement video compression techniques such as those described in the standards defined by MPEG-2, MPEG-4, ITU-T H.263, ITU-T H.264/MPEG-4, part 10, Advanced Video Coding. video (AVC), the High Efficiency Video Coding (HEVC) standard currently under development, and extensions of such standards, to transmit, receive, and store digital information more efficiently.

[0004] Video compression techniques perform spatial prediction (intra-picture) and/or temporal prediction (inter-picture) to reduce or remove inherent redundancy in video sequences. For block-based video encoding, a video slice can be partitioned into video blocks which may also be referred to as treeblocks, encoding units (CUs) and/or encoding nodes. Video blocks in an intra-coded (I) slice of an image are encoded using spatial prediction with respect to reference samples in neighboring blocks in the same image. Video blocks in an intercoded slice (P or B) of an image can use spatial prediction with respect to reference samples in neighboring blocks in the same image or temporal prediction with respect to reference samples in other reference images. Images may be referred to as frames, and reference images may be referred to as frames of reference.

summary

[0005] In general, this disclosure describes techniques for encoding and decoding video data. A video encoder generates candidate lists for each prediction unit (PU) of a current encoding unit (CU) according to merge mode or an advanced motion vector prediction (AMVP) process. The video encoder generates the candidate lists in such a way that each candidate in the candidate lists that is generated based on motion information from at least one other PU is generated without using motion information from any other PU that belongs to the current CU. Candidates that are generated based on movement information from other PUs can include original candidates that indicate movement information from other PUs and candidates that indicate movement information derived from movement information from one or more other PUs. After generating the candidate list for a PU, the video encoder can generate a predictive video block for the PU based on one or more reference blocks indicated by the PU's motion information. PU movement information is determinable based on movement information indicated by one or more candidates selected from the candidate list for the PU. Since none of the candidates in the candidate lists for the PUs of the current CU are generated using motion information from any other PUs of the current CU, the video encoder can generate the candidate lists in parallel for one or more of the PUs of the current CU.

[0006] The present disclosure describes a method for encoding video data. The method comprises generating, for each PU in a plurality of PUs belonging to a current CU, a candidate list for the PU such that each candidate in the candidate list that is generated based on movement information from at least another PU is generated without using motion information from any other PU that belongs to the current CU. Furthermore, the method comprises generating, for each PU belonging to the current CU, a predictive video block for the PU based on a reference block indicated by PU motion information, the PU motion information being determinable based on on movement information indicated by a candidate selected from the candidate list for the PU.

[0007] Furthermore, this disclosure describes a video encoding device comprising one or more processors configured to generate, for each PU in a plurality of PUs belonging to a current CU, a list of candidates for the PU in such a way that each candidate in the candidate list that is generated based on movement information from at least one other PU is generated without using movement information from any of the PUs that belong to the current CU. One or more processors are further configured to generate, for each PU that belongs to the current CU, a predictive video block for the PU based on a reference block indicated by PU motion information, the PU motion information being determinable. based on movement information indicated by a candidate selected from the candidate list for the PU.

[0008] Furthermore, this disclosure describes a video encoding device comprising mechanisms for generating, for each PU in a plurality of PUs belonging to a current CU, a list of candidates for the PU such that each candidate in the candidate list that is generated based on movement information from any of the PUs that belong to the current CU. Furthermore, the video encoding device comprises mechanisms to generate, for each PU belonging to the current CU, a predictive video block for the PU based on a reference block indicated by the PU's motion information, the PU's motion information. PU being determinable based on movement information indicated by a candidate selected from the candidate list for the PU.

[0009] Further, the present disclosure describes a computer program product that comprises one or more computer-readable storage media that stores information that, when executed, configures one or more processors to generate, for each PU in a plurality of PUs that belong to a current CU, a candidate list for the PU such that each candidate in the candidate list that is generated based on movement information from at least one other PU is generated without using movement information from any of the PUs that belong to the current CU. The instructions also configure one or more processors to generate, for each PU that belongs to the current CU, a predictive video block for the PU based on a reference block indicated by PU motion information, the PU motion information being determinable. based on movement information indicated by a candidate selected from the candidate list for the PU.

[0010] The details of one or more examples are shown in the attached drawings and description below. Other features, objects and advantages will be apparent from the description and drawings, and from the claims.

Brief description of drawings

[0011] Figure 1 is a block diagram illustrating an example video encoding system that can utilize the techniques of the present disclosure.

[0012] Figure 2 is a block diagram illustrating an example video encoder that is configured to implement the techniques of the present disclosure.

[0013] Fig. 3 is a block diagram illustrating an example video decoder that is configured to implement the techniques of the present disclosure.

[0014] Figure 4 is a block diagram illustrating an example configuration of an inter prediction module.

[0015] Figure 5 is a flowchart illustrating an example merge operation.

[0016] Figure 6 is a flowchart illustrating an example advanced motion vector prediction (AMVP) operation.

[0017] Figure 7 is a flowchart illustrating an example motion compensation operation performed by a video decoder.

[0018] Figure 8A is a conceptual diagram illustrating a coding unit (CU) and exemplary source locations associated with CU.

[0019] Figure 8B is a conceptual diagram illustrating a CU and exemplary alternative source locations associated with the CU.

[0020] Figure 9A is a conceptual diagram illustrating example reference index source locations on the left of a 2NxN partitioned CU.

[0021] Figure 9B is a conceptual diagram illustrating example reference index source locations on the left of a 2NxN partitioned CU.

[0022] Figure 9C is a conceptual diagram illustrating example reference index source locations above a 2NxN partitioned CU.

[0023] Figure 9D is a conceptual diagram illustrating example reference index source locations above an Nx2N partitioned CU.

[0024] Figure 9E is a conceptual diagram illustrating example reference index source locations on the left of an NxN partitioned CU.

[0025] Figure 9F is a conceptual diagram illustrating example reference index source locations above an NxN partitioned CU.

[0026] Fig. 10A is a conceptual diagram illustrating an example reference index source location on the left of a 2NxN partitioned CU.

[0027] Fig. 10B is a conceptual diagram illustrating an example reference index source location on the left of an Nx2N partitioned CU.

[0028] Fig. 10C is a conceptual diagram illustrating an example reference index source location above a 2NxN partitioned CU.

[0029] Figure 10D is a conceptual diagram illustrating an example reference index source location above an Nx2N partitioned CU.

[0030] Figure 10E is a conceptual diagram illustrating an example reference index source location to the left of the NxN partitioned CU.

[0031] Figure 11 is a graph illustrating an example operation to generate a temporal candidate for a PU.

[0032] Figure 12 is a flowchart illustrating a first example operation to generate a candidate list for a PU.

[0033] Figure 13 is a flowchart illustrating a second example operation to generate a candidate list for a PU.

[0034] Fig. 14A is a conceptual diagram illustrating an example spatial candidate origin location associated with a left PU of an Nx2N partitioned CU.

[0035] Figure 14B is a conceptual diagram illustrating example spatial candidate source locations associated with a lower PU of a 2NxN partitioned CU.

[0036] Figures 15A-15D are conceptual diagrams illustrating example spatial candidate source locations associated with Pus of an NxN partitioned CU.

Detailed Description

[0037] A video encoder can perform inter prediction to reduce temporal redundancy between images. As described below, a coding unit (CU) can have a plurality of prediction units (PUs). In other words, a plurality of PUs can belong to CUs. When the video encoder performs inter prediction, the video encoder can signal motion information to the PUs. A PU's motion information can include a reference image index, a motion vector, and a predictive direction indicator. The motion vector can indicate an offset between a PU video block and a PU reference block. The PU reference block can be a portion of the reference image that is similar to the PU video block. The reference block can be in a reference image indicated by the reference image index and the prediction direction indicator.

[0038] To reduce the number of bits required to represent the motion information of the PUs, the video encoder can generate candidate lists for each of the PUs according to a fusion mode or an advanced motion vector prediction process ( MPV). Each candidate in a candidate list for a PU can indicate movement information. The movement information indicated by some of the candidates in the candidate list may be based on the movement information of other PUs. For example, candidate lists can include “original” candidates that indicate movement information from PUs that cover specified spatial or temporal candidate locations. Also, in some examples, candidate lists may include candidates generated by combining partial motion vectors from different original candidates. Additionally, candidate lists can include “artificial” candidates that are not generated based on motion information from other PUs, such as candidates that indicate motion vectors having zero magnitude.

[0039] According to the techniques of this disclosure, the video encoder can generate candidate list for each PU of a CU such that each candidate in the candidate lists that is generated based on motion information from at least one other PU generated without using transaction information from any other PU that belong to the CU. As none of the candidates in the candidate lists are generated using motion information from any other PU of the same CU, the video encoder may be able to generate the candidate lists in parallel. Generating candidate lists in parallel can facilitate video encoder implementation. In some cases, generating candidate lists in parallel may be faster than generating candidate lists in series.

[0040] After generating the candidate list for a CU PU, the video encoder can select a candidate from the candidate list and transmit a candidate index in a bitstream. The candidate index can indicate a position of the selected candidate in the candidate list. The video encoder can also generate a predictive video block for the PU based on a reference block indicated by the PU's motion information. The PU movement information can be determinable based on the movement information indicated by the selected candidate. For example, in merge mode, the PU's movement information can be the same as the movement information indicated by the selected candidate. In AMVP mode, the PU motion information can be determined based on a PU motion vector difference and the motion information indicated by the selected candidate. The video encoder can generate one or more residual video blocks for the CU based on the predictive video blocks for the CU PUs and an original video block for the CU. The video encoder can then encode and transmit one or more residual video blocks in the bitstream.

[0041] The video decoder can generate candidate lists for each of the CU's PUs. According to the techniques of this disclosure, the video decoder can, for each of the PUs, generate a candidate list for the PU such that each candidate in the candidate list that is generated based on motion information of at least another PU is generated without using motion information from any other PU that belongs to the CU. Candidate lists generated for PUs by the video decoder can be the same as candidate lists generated for PUs by the video encoder. As the video decoder can generate each of the candidates in the candidate lists without using motion information from any other PU of the CU, the video decoder may be able to generate the candidate lists in parallel.

[0042] The bit stream may include data identifying candidates selected from the PU candidate lists. the video decoder can determine motion information from the PUs based on motion information indicated by candidates selected from the PU candidate lists. the video decoder can identify one or more reference blocks for the PUs based on the motion information of the PUs. after identifying one or more reference blocks from a PU, the video decoder can generate a predictive video block for the PU based on one or more reference blocks from the PU. The video decoder can reconstruct a video block for the CU based on the predictive video blocks for the CU's PUs and one or more residual video blocks for the CU.

[0043] Therefore, the techniques of this disclosure can enable a video encoder (i.e., a video encoder or a video decoder) to generate, for each PU in a plurality of PUs belonging to a current CU, a list of candidates for the PU such that each candidate in the candidate list that is generated based on movement information from at least one other PU is generated without using movement information from any other PU that belongs to the current CU. The video encoder can generate, for each PU belonging to the current CU, a predictive video block for the PU based on a reference block indicated by PU motion information, the PU motion information being determinable based on movement information indicated by a candidate selected from the candidate list for the PU.

[0044] For ease of explanation, this disclosure may describe locations or video blocks as having various spatial relationships with Cus or PUs. such a description can be interpreted to mean that the locations or video blocks have the various spatial relationships to the video blocks associated with the Cus or PUs. further, this revelation may refer to a PU that a video encoder is currently encoding as the current PU. This revelation may refer to a CU that a video encoder is currently encoding as the current CU. This revelation can refer to an image that a video encoder is currently encoding as the current image.

[0045] The attached drawings illustrate examples. Elements indicated by reference numerals in the accompanying drawings correspond to elements indicated by similar reference numerals in the following description. In this revelation, elements having names that begin with ordinal words (eg, “first”, “second”, “third”, and so on) do not necessarily indicate that the elements have a specific order. Instead, such original words are merely used to refer to different elements of an equal or similar type.

[0046] Figure 1 is a block diagram illustrating an example video encoding system 10 that can utilize the techniques of such disclosure. As used and described herein, the term "video encoder" refers generically to both video encoders and video decoders. In this disclosure, the terms “video encoding” or “encoding” may refer to video encoding and video decoding.

[0047] As shown in Figure 1, the video encoding system 10 includes a source device 12 and a target device 14. The source device 12 generates encoded video data. Therefore, the source device 12 can be referred to as a video encoding device. The target device 14 can decode the encoded video data generated by the source device 12. Therefore, the target device 14 can be referred to as a video decoding device. Source device 12 and target device 14 can be examples of video encoding devices.

[0048] Source device 12 and target device 14 can comprise a wide range of devices, including desktop computers, mobile computing devices, notebook computers (e.g. laptop), tablet computers, frequency converters, telephones such as so-called “smart” phones, televisions, cameras, display devices, digital media players, video game consoles, in-car computers, or the like. In some examples, source device 12 and target device 14 may be equipped for wireless communication.

[0049] The target device 14 may receive encoded video data from the source device 12 via a channel 16. The channel 16 may comprise a type of medium or device capable of moving the encoded video data from the device from source 12 to target device 14. In one example, channel 16 may comprise a communication medium that enables source device 12 to transmit encoded video data directly to target device 14 in real time. In this example, the source device 12 can modulate the encoded video data in accordance with a communication standard, such as a wireless communication protocol, and can transmit the modulated video data to the target device 14. The communication medium may comprise a wireless or wired communication medium, such as a radio frequency (RF) spectrum or one or more physical transmission lines. The communication medium may be part of a packet-based network, such as a local area network, a remote area network, or a global network such as the Internet. The communication medium may include routers, switches, base stations, or other equipment that facilitates communication from source device 12 to destination device 14.

[0050] In another example, channel 16 may correspond to a storage medium that stores the encoded video data generated by the source device 12. In this example, the destination device 14 may access the storage medium through disk access or card access. The storage medium may include a variety of locally accessed data storage media such as Blu-ray Discs, DVDs, CD-ROMs, flash memory, or other digital storage media suitable for storing encoded video data. In a further example, channel 16 may include a file server or other intermediate storage device that stores the encoded video generated by the source device 12. In this example, the destination device 14 may access encoded video data stored on the streaming server. file or other intermediate storage device via streaming or download. The file server can be a type of server capable of storing encoded video data and transmitting the encoded video data to the target device 14. Example file servers include network servers (e.g. for a website), servers file transfer protocol (FTP), network-attached storage (NAS) devices, and local disk drives. The target device 14 can access the encoded video data over a standard data connection, including an Internet connection. Examples of data connection types may include wireless channels (e.g. Wi-Fi connections), wired connections (e.g. DSL, cable modem, etc.), or combinations of both that are appropriate for accessing data from encoded video stored on a file server. The transmission of encoded video data from the file server can be a streaming transmission, a download transmission, or a combination of both.

[0051] The techniques of this revelation are not limited to wireless applications or scenarios. The techniques can be applied to video encoding in support of any of a variety of multimedia applications, such as over-the-air television broadcasts, cable television broadcasts, satellite television broadcasts, streaming video broadcasts, for example, through Internet, encoding digital video for storage on a data storage medium, decoding digital video stored on a data storage medium, or other applications. In some examples, the video encoding system 10 may be configured to support single or duplex video transmission to support applications such as video streaming, video repeating, video broadcasting, and/or video telephony.

[0052] In the example of Figure 1, the source device 12 includes a video source 18, video encoder 20 and an output interface 22. In some cases, the output interface 22 may include a modulator/demodulator (modem) and/or a transmitter. In source device 12, video source 18 may include a source such as a video capture device, e.g. a video camera, a video file containing previously captured video data, a video feed interface for receiving video data from a video content provider, and/or a computer graphics system to generate video data, or a combination of such sources.

[0053] Video encoder 20 can encode captured, pre-captured or computer generated video data. The encoded video data may be transmitted directly to the target device 14 through the output interface 22 of the source device 12. The encoded video data may also be stored on a storage medium or a file server for later access by the target device 14 for decoding and/or playback.

[0054] In the example of Figure 1, the destination device 14 includes an input interface 28, a video decoder 30, and a display device 32. In some cases, the input interface 28 may include a receiver and/or a modem. The input interface 28 of the target device 14 receives encoded video data over channel 16. The encoded video data may include a variety of syntax elements generated by the video encoder 20 that represent the video data. Such syntax elements may be included with encoded video data transmitted on a communication medium, stored on a storage medium, or stored on a file server.

[0055] Display device 32 may be integrated with, or external to, target device 14. In some examples, target device 14 may include an integrated display device and may also be configured to interface with a display device external. In other examples, the target device 14 may be a display device. In general, the display device 32 displays the decoded video data to a user. The display device 32 may comprise any of a variety of display devices such as a liquid crystal display (LCD), a plasma display, an organic light-emitting diode (OLED) display, or other type of display device. The video encoder 20 and video decoder 30 can operate according to a video compression standard, such as the High Efficiency Video Coding (HEVC) standard currently under development, and can conform to a HEVC Test Model ( HM). A recent draft of the upcoming HEVC standard, referred to as “HEVC Working draft 7” or “WD7”, is described in document JCTVC-11003_d54, Bross et al., “High efficiency video coding (HEVC) text specification draft 7”, Joint Collaborative team on video coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 9th Meeting: Geneva, Switzerland, May 2012, which, as of July 19, 2012, is downloadable at: http://phenix.int-evry.fr/jct/doc end user/documents/9 Geneva/wg11/JCTVC-11003-v6.zip, the entire contents of which are incorporated herein by reference. Alternatively, the video encoder 20 and video decoder 30 may operate in accordance with other proprietary or industrial standards, such as the ITU-T H.264 standard, alternatively referred to as MPEG-4, part 10, Advanced Video Coding (AVC ), or extensions of such standards. The techniques of this disclosure, however, are not limited to any specific coding technique or standard. Other examples of video compression standards and techniques include MPEG-2, ITU-T H.263, and open source or proprietary compression formats such as VP8 and related formats.

[0056] Although not shown in Figure 1, the video encoder 20 and video decoder 30 may be individually integrated with an audio encoder and decoder, and may include appropriate MUX-DEMUX units, or other hardware and software, to handle encoding both audio and video into a common data stream or separate data streams. If applicable, in some examples, MUX-DEMUX units may conform to the ITU H.223 multiplexer protocol, or other protocols such as the User Datagram Protocol (UDP).

[0057] Again, Figure 1 is merely an example and the techniques of this disclosure may apply to video encoding scenarios (e.g. video encoding or video decoding) that do not necessarily include any data communication between video devices. encoding and decoding. In other examples, data may be retrieved from local memory, streamed over a network, or similar. An encoding device can encode and store data into memory, and/or a decode device can retrieve and decode data from memory. In many examples, encoding and decoding is performed by devices that do not communicate, but simply encode data into memory and/or retrieve and decode data from memory.

[0058] Video encoder 20 and video decoder 30 may be implemented individually, as any of a variety of appropriate encoder circuitry, such as one or more microprocessors, digital signal processors (DSPs), application integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, software, hardware, firmware, or any combination thereof. When the techniques are partially implemented in software, a device may store instructions for the software on an appropriate, non-transient, computer-readable medium and may execute the instructions in hardware using one or more processors to perform the techniques of such disclosure. Each of the video encoder 20 and video decoder 30 may be included in one or more encoders or decoders, any of which may be integrated as part of a combined encoder/decoder (CODEC) in a respective device.

[0059] As mentioned briefly above, the video encoder 20 encodes video data. Video data may comprise one or more images. Each of the images is a still image forming part of a video. In some cases, an image may be referred to as a video “frame”. When the video encoder 20 encodes the video data, the video encoder 20 can generate a bit stream. The bit stream may include a sequence of bits that form an encoded representation of the video data. The bitstream can include encoded images and associated data. An encoded image is an encoded representation of an image.

[0060] To generate the bit stream, the video encoder 20 can perform encoding operations on each image in the video data. When the video encoder 20 performs encoding operations on the images, the video encoder 20 can generate a series of encoded images and associated data. Associated data can include sequence parameter sets, image parameter sets, adaptation parameter sets, and other syntax structures. A sequence parameter set (SPS) can contain parameters applicable to zero or more image sequences. An image parameter set (PPS) can contain parameters applicable to zero or more images. An adaptation parameter set (APS) can contain parameters applicable to zero or more images. Parameters in an APS can be parameters that are more likely to change than parameters in a PPS.

[0061] To generate an encoded image, the video encoder 20 can split an image and equally sized video blocks. A video block can be a two-dimensional set of samples. Each of the video blocks is associated with a treeblock. In some cases, a treeblock may be referred to as a major coding unit (LCU). HEVC treeblocks can be broadly analogous to macroblocks from earlier standards such as H.264/AVC. However, a treeblock is not necessarily limited to a specific size and can include one or more encoding units (CUs). The video encoder 20 can use quadtree splitting to split the video blocks of treeblocks into video blocks associated with CUs, hence the name “treeblocks.”

[0062] In some examples, the video encoder 20 may split an image into a plurality of slices. Each of the slices can include an integer number of CUs. In some cases, a slice comprises an integer number of treeblocks. In other cases, a slice boundary may be inside a treeblock.

[0063] As part of performing an encoding operation on an image, the video encoder 20 may perform encoding operations on each slice of the image. When the video encoder 20 performs an encoding operation on a slice, the video encoder 20 can generate encoded data associated with the slice. The encoded data associated with the slice may be referred to as an “encoded slice.”

[0064] To generate an encoded slice, the video encoder 20 can perform encoding operations on each treeblock in a slice. When the video encoder 20 performs an encoding operation on a treeblock, the video encoder 20 can generate an encoded treeblock. The encoded treeblock can comprise data representing an encoded version of the treeblock.

[0065] When the video encoder 20 generates an encoded slice, the video encoder 20 can perform encoding operations on (i.e., encode) the treeblocks (which in this case represent larger encoding units) in the slice according to an order raster scan. In other words, the video encoder 20 can encode the treeblocks of the slice in an order that proceeds from left to right through a topmost row of treeblocks in the slice, then proceeds from left to right through a lower row. next number of treeblocks, and so on until video encoder 20 has encoded each of the treeblocks in the slice.

[0066] As a result of encoding the treeblocks according to the raster scan order, the treeblocks above and to the left of a given treeblock may have been encoded, but treeblocks below and to the right of the given treeblock have not yet been encoded. Consequently, the video encoder 20 may be able to access information generated by encoding treeblocks above and to the left of the given treeblock when encoding the given treeblock. However, the video encoder 20 may be unable to access information generated by encoding treeblocks below and to the right of the given treeblock when encoding the given treeblock.

[0067] To generate an encoded treeblock, the video encoder 20 can recursively perform quadtree splitting on the treeblock video block to split the video block into progressively smaller video blocks. Each of the smaller video blocks can be associated with a different CU. For example, the video encoder 20 can divide the video block of a treeblock into four equally sized sub-blocks, divide one or more of the sub-blocks into four equally sized sub-sub-blocks, and so on. A partitioned CU can be a CU whose video block is divided into video blocks associated with other CUs. A non-partitioned CU can be a CU whose video block is not divided into video blocks associated with other CUs.

[0068] One or more syntax elements in the bitstream may indicate a maximum number of times the video encoder 20 can split the video block of a treeblock. A video block of a CU can be square-shaped. The video block size of a CU (that is, the size of the CU) can range from 8x8 pixels up to the size of a video block of a treeblock (that is, the size of the treeblock) with a maximum of 64x64 pixels or larger.

[0069] The video encoder 20 can perform encoding operations on (i.e., encode) each CU of a treeblock according to a z-scan order. in other words, the video encoder 20 can encode an upper-left CU, an upper-right CU, a lower-left CU, and then a lower-right CU, in that order. When the video encoder 20 performs an encoding operation on a partitioned CU, the video encoder 20 can encode CUs associated with sub-blocks of the video block of the partitioned CU according to the z-scan order. In other words, the video encoder 20 can encode a CU associated with an upper-left sub-block, a CU associated with an upper-right sub-block, a CU associated with a lower-left sub-block, and then a CU associated with a lower-right sub-block, in that order.

[0070] As a result of encoding the CUs of a treeblock according to a z-scan order, the CUs above, above and to the left, above and to the right, left, and below and to the left of a given CU may have been encoded. CUs below or to the right of the given CU have not been coded yet. Consequently, the video encoder 20 may be able to access information generated by encoding some CUs that are neighbors of the given CU by encoding the given CU. However, the video encoder 20 may be unable to access information generated by encoding other CUs that are neighbors of the given CU when encoding the given CU.

[0071] When the video encoder 20 encodes a non-partitioned CU, the video encoder 20 may generate one or more prediction units (PUs) for the CU. Each of the CU PUs can be associated with a different video block in the CU video block. The video encoder 20 can generate a predictive video block for each PU of the CU. A PU's predictive video block can be a sample block. The video encoder 20 can use intra prediction or inter prediction to generate the predictive video block for a PU.

[0072] When the video encoder 20 uses intraprediction to generate the predictive video block of a PU, the video encoder 20 can generate the predictive video block of the PU based on decoded samples of the image associated with the PU. If the video encoder 20 uses intraprediction to generate blocks of predictive video from the PUs of a CU, the CU is an intrapredicted CU. When the video encoder 20 uses interprediction to generate the PU predictive video block, the video encoder 20 can generate the PU predictive video block based on decoded samples of one or more different images of the image associated with the PU. If the video encoder 20 uses interprediction to generate blocks of predictive video from the PUs of a CU, the CU is an interpredicted CU.

[0073] Furthermore, when the video encoder 20 uses interprediction to generate a block of predictive video for a PU, the video encoder 20 can generate motion information for the PU. Motion information for a PU can indicate one or more PU reference blocks. Each PU reference block can be a video block in a reference image. The reference image can be a different image than the image associated with the PU. In some cases, a reference block of a PU may also be referred to as the “reference sample” of the PU. The video encoder 20 can generate the predictive video block for the PU based on the reference blocks of the PU.

[0074] After the video encoder 20 generates blocks of predictive video for one or more PUs of a CU, the video encoder 20 can generate residual data for the CU based on the blocks of predictive video for the PUs of the CU. Residual data for the CU may indicate differences between samples in the predictive video blocks for the CU PUs and the original video block for the CU.

[0075] Also, as part of performing an encoding operation on a non-partitioned CU, the video encoder 20 can perform recursive quadtree division on the CU residual data to split the CU residual data into one or more blocks of the data residuals (ie residual video blocks) associated with CU transform units (Teus). Each TU of a CU can be associated with a different residual video block.

[0076] The video encoder 20 may apply one or more transforms to residual video blocks associated with TUs to generate transform coefficient blocks (i.e., transform coefficient blocks) associated with TUs. Conceptually, a transform coefficient block can be a two-dimensional (2D) array of transform coefficients.

[0077] After generating a transform coefficient block, the video encoder 20 can perform a quantization process on the transform coefficient block. Quantization generically refers to a process in which transform coefficients are quantized to possibly reduce the amount of data used to represent transform coefficients by providing additional compression. The quantization process can reduce the bit depth associated with some or all of the transform coefficients. For example, an n-bit transform coefficient can be rounded to an m-bit transform coefficient during quantization, where n is greater than m.

[0078] Video encoder 20 can associate each CU with a quantization parameter value (QP). The QP value associated with a CU can determine how the video encoder 20 quantizes transform coefficient blocks associated with the CU. The video encoder 20 can adjust the degree of quantization applied to the transform coefficient blocks associated with a CU by adjusting the QP value associated with the CU.

[0079] After the video encoder 20 quantizes a transform coefficient block, the video encoder 20 can generate sets of syntax elements representing the transform coefficients in the quantized transform coefficient block. The video encoder 20 may apply entropy encoding operations, such as Context Adaptive Binary Arithmetic Encoding (CABAC) operations, to some of these syntax elements.

[0080] The bit stream generated by video encoder 20 may include a number of Network Abstraction Layer (NAL) units. Each of the NAL units can be a syntax structure containing an indication of a data type in the NAL unit and bytes containing the data. For example, a NAL unit may contain data representing a sequence parameter set, an image parameter set, an encoded slice, supplemental enhancement information (SEI), an access unit delimiter, stuffing data, or other type. of data. The data in a NAL unit can include multiple syntax structures.

[0081] The video decoder 30 may receive the bit stream generated by the video encoder 20. The bit stream may include an encoded representation of the video data encoded by the video encoder 20. When the video decoder 30 receives the stream of bits, the video decoder 30 can perform an analysis operation on the bit stream. When the video decoder 30 performs the parsing operation, the video decoder 30 can extract syntax elements from the bit stream. The video decoder 30 can reconstruct the images of the video data based on the syntax elements extracted from the bit stream. The process for reconstructing the video data based on the syntax elements may be generally reciprocal to the process performed by the video encoder 20 to generate the syntax elements.

[0082] After the video decoder 30 extracts the syntax elements associated with a CU, the video decoder 30 can generate predictive video blocks for the PUs of the CU based on the syntax elements. In addition, the video decoder 30 can inversely quantize transform coefficient blocks associated with CU TUs. The video decoder 30 can perform inverse transforms on the transform coefficient blocks to reconstruct residual video blocks associated with the CU's TUs. After generating the predictive video blocks and reconstructing the residual video blocks, the video decoder 30 can reconstruct the CU video block based on the predictive video blocks and residual video blocks. In this way, the video decoder 30 can reconstruct the video blocks of the CUs based on the syntax elements in the bitstream.

[0083] As briefly described above, the video encoder 20 can use inter prediction to generate predictive video blocks and motion information for the PUs of a CU. In many cases, the motion information from a given PU is likely to be the same or similar to the motion information from one or more nearby PUs (i.e., PUs whose video blocks are spatially or temporally close to the video block of the given PU). ). As nearby PUs often have similar motion information, the video encoder 20 can encode the motion information of a given PU with reference to the motion information of a nearby PU. Encoding the given PU's motion information with reference to the next PU's motion information can reduce the number of bits required in the bit stream to indicate the given PU's motion information.

[0084] The video encoder 20 can encode the motion information of a given PU with reference to the motion information of a nearby PU in various ways. For example, the video encoder 20 can indicate that the motion information of the given PU is the same as the motion information of the next PU. This disclosure may use the phrase “merger mode” to refer to the indication that the movement information of a given PU is the same as the movement information of a nearby PU or can be derived from the movement information of nearby PUs. In another example, the video encoder 20 can calculate a motion vector difference (MVD) for the given PU. The MVD indicates the difference between a given PU motion vector and a nearby PU motion vector. In this example, the video encoder 20 can include the MVD in the given PU's motion information instead of the given PU's motion vector. A smaller number of bits may be needed in the bit stream to represent the MVD than the given PU motion vector. This revelation may use the phrase “advanced motion vector prediction” (AMVP) mode to refer to the signaling of motion information from a PU given in this mode.

[0085] To signal the motion information of a given PU using merge mode or AMVP mode, the video encoder 20 can generate a candidate list for the given PU. The candidate list can include one or more candidates. Each of the candidates in the candidate list for the given PU can specify movement information. The motion information indicated by a candidate can include a motion vector, a reference image index, and a prediction direction indicator. Candidates in the candidate list can include candidates that are based on (e.g. indicate, are derived from, etc.) movement information from PUs other than the given PU, with the proviso that the other PUs do not belong to the CU associated with the PU given.

[0086] After generating the candidate list for a PU, the video encoder 20 can select one of the candidates from the candidate list for the PU. The video encoder 20 can transmit a candidate index to the PU. The candidate index can identify a position in the candidate list for the selected candidate.

[0087] In addition, the video encoder 20 can generate a predictive video block for the PU based on reference blocks indicated by the PU's motion information. PU movement information can be determinable based on movement information indicated by the candidate selected in the candidate list for the PU. For example, in merge mode, the PU's movement information can be the same as the movement information indicated by the selected candidate. In AMVP mode, the PU motion information can be determinable based on a motion vector difference for the PU and the motion information indicated by the selected candidate. The video encoder 20 can process the predictive video block for the PU as described above.

[0088] When the video decoder 30 receives the bit stream, the video decoder 30 can generate candidate lists for each of the CU's PUs. The candidate lists generated for the PUs by the video decoder 30 may be the same as the candidate lists generated for the PUs by the video encoder 20. A syntax parsed from the bitstream may indicate the positions of selected candidates in the candidate lists. of PUs. after generating the candidate list for a PU, the video decoder 30 may generate a predictive video block for the PU based on one or more reference blocks indicated by motion information from the PU. The video decoder 30 can determine the motion information of the PU based on motion information indicated by the candidate selected in the candidate list for the PU. The video decoder 30 can reconstruct a video block for the CU based on the predictive video blocks for the PUs and residual video blocks for the CU.

[0089] While encoding the motion information of a first PU with reference to the motion information of a second PU can reduce the number of bits required in the bit stream to indicate the motion information of the first PU, doing so can prevent the video encoder 20 encodes the motion information of the first PU until after the video encoder 20 has encoded the motion information of the second PU. Consequently, the video encoder 20 may be unable to encode the motion information of the first and second PUs in parallel. The ability to encode motion information from multiple PUs in parallel can increase the transmission capacity of the video encoder 20.

[0090] Similarly, encoding the motion information of the first PU with reference to the motion information of the second PU can prevent the video decoder 30 from determining the motion information of the first PU until after the video decoder 30 has determined the movement information of the second PU. Consequently, the video decoder 30 may be unable to generate predictive blocks for the first and second PUs in parallel. The ability to decode motion information from multiple PUs in parallel can increase the transmission capacity of the video decoder 30.

[0091] According to the techniques of that disclosure, the video encoder 20 and video decoder 30 can generate candidate lists for each PU of the CU such that each candidate in the candidate list for the PU that is generated based on movement information from at least one other PU is generated without using movement information from any other PU of the same CU. As no candidate is generated using the motion information of any other PU of the same CU, the video encoder 20 can encode the motion information of multiple PUs of the CU in parallel. As no candidate is generated using the motion information of any other PU of the same CU, the video decoder 30 can decode the motion information of multiple PUs of the CU in parallel. This can increase the speed at which video encoder 20 can encode video data and video decoder 30 can decode video data.

[0092] In this way, a video encoder (e.g., video encoder 20 or video decoder 30) can generate, for each PU in a plurality of PUs that belong to a current CU, a list of candidates for the PU of such that each candidate in the candidate list that is generated based on movement information from at least one other PU is generated without using movement information from any other PU that belongs to the current CU. The video encoder can generate, for each PU that belongs to the current CU, a predictive video block for the PU based on a reference block indicated by PU motion information, the PU motion information being determinable based on PU movement information, the PU movement information being determinable based on movement information indicated by a candidate selected from the candidate list for the PU.

[0093] Figure 2 is a block diagram illustrating an example video encoder 20 that is configured to implement the techniques of this disclosure. Figure 2 is provided for the purpose of explanation and should not be considered limiting the techniques as amply exemplified and described in this disclosure. For purposes of explanation, this disclosure describes the video encoder 20 in the context of HEVC encoding. However, the techniques of this disclosure may be applicable for other encoding methods or standards.

[0094] In the example of Figure 2, the video encoder 20 includes a plurality of functional components. The functional components of the video encoder 20 include a prediction module 100, a residual generation module 102, a transform module 104, a quantization module 106, an inverse quantization module 108, an inverse transform module 110, a reconstruction module 112, a filter module 113, a decoded image buffer 114 and an entropy encoding module 116. The prediction module 100 includes an inter prediction module 121, motion estimation module 122, a motion compensation module 124, and an intraprediction module 126. In other examples, the video encoder 20 may include a higher number, a lower number, or different functional components. Furthermore, the motion estimation module 122 and motion compensation module 124 can be highly integrated, but are represented in the example of Figure 2 separately for purposes of explanation.

[0095] Video encoder 20 can receive video data. The video encoder 20 can receive video data from various sources. For example, video encoder 20 may receive video data from video source 18 (FIG. 1) or another source. Video data can represent a series of images. To encode the video data, the video encoder 20 can perform an encoding operation on each of the images. As part of performing encoding operations on an image, the video encoder 20 may perform encoding operations on each slice of the image. As part of performing an encoding operation on a slice, the video encoder 20 may perform encoding operations on treeblocks on the slice.

[0096] As part of performing an encoding operation on a treeblock, the prediction module 100 can perform quadtree splitting on the video block of the treeblock to split the video block into progressively smaller video blocks. Each of the smaller video blocks can be associated with a different CU. For example, the prediction module 100 can split a video block of a treeblock into four sub-blocks of equal size, split one or more of the sub-blocks into four sub-sub-blocks of equal size, and so on.

[0097] Video block sizes associated with CUs can range from 8x8 samples to treeblock size with a maximum of 64x64 samples or greater. In this revelation, “NxN” and “N by N” can be used interchangeably to refer to the sample dimensions of a video block in terms of vertical and horizontal dimensions, for example, 16x16 samples or 16x16 samples. In In general, a 16x16 video block has sixteen samples in a vertical direction (y = 16) and sixteen samples in a horizontal direction (x = 16). Similarly, an NxN block has generically N samples in a vertical direction and N samples in a horizontal direction, where N represents a non-negative integer value.

[0098] Also, as part of performing the encoding operation on a treeblock, the prediction module 100 can generate a hierarchical quadtree data structure for the treeblock. For example, a treeblock might correspond to a root node of the quadtree data structure. If the prediction module 100 divides the treeblock's video block into four sub-blocks, the root node has four child nodes in the quadtree data structure. Each of the child nodes corresponds to a CU associated with one of the sub-blocks. If the prediction module 100 divides one of the sub-blocks into four sub-sub-blocks, the node corresponding to the CU associated with the sub-block may have four child nodes, each of which corresponds to a CU associated with one of the sub-blocks. sub-blocks.

[0099] Each quadtree data structure node can contain syntax data (eg syntax elements) for the corresponding treeblock or CU. For example, a node on the quadtree may include a split indicator that indicates whether the CU video block corresponding to the node is split (i.e., shared) into four sub-blocks. Syntax elements for a CU can be defined recursively, and may depend on whether the CU's video block is divided into sub-blocks. A CU whose video block is not split can correspond to a leaf node in the quadtree data structure. An encoded treeblock can include data based on the quadtree data structure for a corresponding treeblock.

[0100] Video encoder 20 can perform encoding operations on each unpartitioned CU of a treeblock. When the video encoder 20 performs an encoding operation on an unpartitioned CU, the video encoder 20 generates data representing an encoded representation of the unpartitioned CU.

[0101] As part of performing an encoding operation on a CU, the prediction module 100 may split the CU video block between one or more CU PUs. Video encoder 20 and video decoder 30 can support various PU sizes. Assuming the size of a specific CU is 2Nx2N, the video encoder 20 and video decoder 30 can support PU sizes of 2Nx2N or NxN for intra prediction, and symmetrical PU sizes of 2Nx2N, 2NxN, Nx2N, NxN, or similar for inter prediction. Video encoder 20 and video decoder 30 can also support asymmetric splitting for PU sizes of 2NxnU, 2NxnD, nLx2N and nRx2N for interprediction. In some examples, the prediction module 100 can perform geometric splitting to divide a CU's video block between CU PUs along a boundary that does not meet the CU's video block sides at right angles.

[0102] Interprediction module 121 can perform interprediction on each PU of the CU. Inter prediction can provide temporal compression. To perform inter-prediction on a PU, the motion estimation module 122 can generate motion information for the PU. The motion compensation module 124 can generate a block of predictive video for the PU based on the motion information and decoded samples of images other than the image associated with the CU (i.e., reference images).

[0103] Slices can be I slices, P slices or B slices. Motion estimation module 122 and motion compensation module 124 can perform different operations for a PU from a CU depending on whether the PU is in an I slice , a P slice or a B slice. In an I slice, all PUs are intrapredicted. Consequently, if the PU is in an I slice, the motion estimation module 122 and motion compensation module 124 do not perform interprediction on the PU.

[0104] If the PU is in a P slice, the image containing the PU is associated with a list of reference images referred to as “list 0”. Each of the reference images in list 0 contains samples that can be used to interpredict other images. When the motion estimation module 122 performs the motion estimation operation with respect to a PU in a slice P, the motion estimation module 122 can fetch the reference images in lane 0 for a reference block for the PU. The PU reference block can be a set of samples, for example a sample block, which most closely correspond to the samples in the PU video block. Motion estimation module 122 can use a variety of metrics to determine how closely a set of samples in a reference image corresponds to samples in a PU's video block. For example, motion estimation module 122 can determine how closely a set of samples in a reference image corresponds to samples in a PU's video block by sum of absolute difference (SAD), sum of squared difference (SSD) or other difference metrics.

[0105] After identifying a reference block of a PU in a slice P, the motion estimation module 122 can generate a reference index that indicates the reference image in list 0 containing the reference block and a motion vector that indicates a spatial displacement between the PU and the reference block. In various examples, motion estimation module 122 can generate motion vectors to varying degrees of accuracy. For example, the motion estimation module 122 can generate motion vectors at one-quarter sample accuracy, one-eighth sample accuracy, or other fractional sample accuracy. In the case of fractional sample accuracy, reference block values can be interpolated from integer position sample values in the reference image. The motion estimation module 122 can transmit the reference index and the motion vector as the motion information of the PU. Motion compensation module 124 can generate a PU predictive video block based on the reference block identified by the PU motion information.

[0106] If the PU is in a slice B, the image containing the PU can be associated with two reference image lists, referred to as “lita 0” and “list 1”. In some examples, an image containing a slice B can be associated with a combination list that is a combination of list 0 and list 1.

[0107] Also, if the PU is in a slice B, the motion estimation module 122 can perform unidirectional prediction or bidirectional prediction for the PU. When the motion estimation module 122 performs one-way prediction for the PU, the motion estimation module 122 can fetch the list 0 or list 1 reference images for a reference block for the PU. The motion estimation module 122 can then generate a reference index that indicates the reference image in list 0 or list 1 that contains the reference block and a motion vector that indicates a spatial displacement between the PU and the reference block. . The motion estimation module 122 can transmit the reference index, a predictive direction indicator, and the motion vector as the PU motion information. The prediction direction indicator can indicate whether the reference index indicates a reference image in list 0 or list 1. Motion compensation module 124 can generate the PU predictive video block based on the reference block indicated by the information. of PU movement.

[0108] When motion estimation module 122 performs bidirectional prediction for a PU, motion estimation module 122 can fetch reference images in list 0 for a reference block for PU and can also fetch reference images in list 1 for another reference block for the PU. The motion estimation module 122 can then generate reference indices that indicate the reference images in list 0 and list 1 containing the reference blocks and motion vectors that indicate spatial displacements between the reference blocks and the PU. The motion estimation module 122 can transmit the reference indices and motion vectors of the PU as the motion information of the PU. The motion compensation module 124 can generate the PU predictive video block based on the reference blocks indicated by the PU motion information.

[0109] In some cases, the motion estimation module 122 does not transmit a complete set of motion information to a PU for entropy encoding module 116. Instead, the motion estimation module 122 may signal the motion information. movement of one PU with reference to movement information of another PU. For example, the motion estimation module 122 can determine that the motion information from the PU is sufficiently similar to the motion information from a neighboring PU. In this example, the motion estimation module 122 may indicate in a syntax structure associated with the PU, a value that indicates to the video decoder 30 that the PU has the same motion information as the neighboring PU or has motion information that can be derived from neighboring PUs. In another example, the motion estimation module 122 can identify in a syntax structure associated with the PU, a motion candidate associated with a neighboring PU and a motion vector difference (MVD). The motion vector difference indicates a difference between the motion vector of the PU and the motion vector of the indicated motion candidate. The video decoder 30 can use the motion vector of the indicated motion candidate and the motion vector difference to determine the motion vector of the PU. By referring to motion information from a motion candidate associated with a first PU when signaling motion information from a second PU, video encoder 20 may be able to signal video information from the second PU using a smaller number of bits.

[0110] As described below with respect to Figures 4-6 and 8-15, the inter-prediction module 121 can generate a candidate list for each PU of a CU. The Interprediction module 121 can generate each candidate list such that each candidate in the candidate list that is generated based on movement information from at least one other PU is generated without using movement information from any of the PUs belonging to CU. . Consequently, the interprediction module 121 may be able to generate the candidate lists for two or more PUs of the CU in parallel. As the inter prediction module 121 may be able to generate the candidate lists for two or more of the CU PUs in parallel, the inter prediction module 121 may be able to generate predictive video blocks for two or more of the CU PUs in parallel. Furthermore, by generating candidate lists for each CU PU in this way, the video encoder 20 can allow a video decoder (e.g., video decoder 30) to generate candidate lists for two or more CU PUs. in parallel and generate predictive video blocks for two or more CU PUs in parallel.

[0111] As part of performing an encoding operation on a CU, the intra prediction module 126 can perform intra prediction on PUs of the CU. Intra prediction can provide spatial compression. When the intra prediction module 126 performs intra prediction on a PU, the intra prediction module 126 can generate prediction data for the PU based on decoded samples from other PUs in the same image. The prediction data for the PU can include a predictive video block and various syntax elements. The intra prediction module 126 can perform intra prediction on PUs in I slices, P slices and B slices.

[0112] To perform intra prediction on a PU, the intra prediction module 126 may use multiple intra prediction modes to generate multiple sets of prediction data for the PU. When the intra prediction module 126 uses an intra prediction mode to generate a set of prediction data for the PU, the intra prediction module 126 can extend samples from the video blocks of neighboring PUs through the video block of the PU in a direction and/or gradient associated with the intra prediction mode. Neighboring PUs can be above, above and to the right, above and to the left, or to the left of the PU, assuming a left-to-right, top-down coding order for the PUs, CUs, and treeblocks. The intra prediction module 126 may utilize various numbers of intra prediction modes, for example, 33 directional intra prediction modes. In some examples, the number of intra prediction modes may depend on the PU size.

[0113] The prediction module 100 can select the prediction data for a PU from among the prediction data generated by the motion compensation module 124 for the PU or the prediction data generated by the intra prediction module 126 for the PU. In some examples, the prediction module 100 selects the prediction data for the PU based on the skew/rate metric from the prediction data sets.

[0114] If prediction module 100 selects prediction data generated by intra prediction module 126, prediction module 100 can signal the intra prediction mode that was used to generate prediction data for the PUs, that is, the selected intra prediction mode. The prediction module 100 can signal the selected intra prediction mode in various ways. For example, the selected intra prediction mode is likely to be the same as the intra prediction mode of a neighboring PU. In other words, the intraprediction mode of the neighboring PU may be the most likely mode for the current PU. In this way, the prediction module 100 can generate a syntax element to indicate that the selected intra-prediction mode is the same as the intra-prediction mode of the neighboring PU.

[0115] After the prediction module 100 selects the prediction data for PUs of a CU, the residual generation module 102 can generate residual data for the CU by subtracting the predictive video blocks of the PUs of the CU from the video block of CU. A CU's residual data can include 2D residual video blocks that correspond to different sample components than the samples in the CU's video block. For example, the residual data may include a residual video block that corresponds to differences between sample luminance components in the CU PUs' predictive video blocks and sample luminance components in the original CU video block. In addition, the CU residual data may include residual video blocks that correspond to the differences between the chrominance components of samples in the predictive video blocks of the CU PUs and the chrominance components of the samples in the original video block of the CU.

[0116] The prediction module 100 can perform quadtree splitting to split the residual video blocks of a CU into sub-blocks. Each unsplitted residual video block can be associated with a TU other than the CU. The sizes and positions of residual video blocks associated with TUs of a CU may or may not be based on the sizes and positions of video blocks associated with PUs of the CU. A quadtree structure known as a “residual quad tree” (RQT) can include nodes associated with each of the residual video blocks. The TUs of a CU can correspond to leaf nodes of the RQT.

[0117] The transform module 104 can generate one or more transform coefficient blocks for each TU of a CU by applying one or more transforms to a residual video block associated with the TU. Each of the transform coefficient blocks can be a 2D matrix of transform coefficients. The transform module 104 can apply multiple transforms to the residual video block associated with a TU. For example, the transform module 104 may apply a discrete cosine transform (DCT), a directional transform, a conceptually similar transform to the residual video block associated with a TU.

[0118] After the transform module 104 generates a transform coefficient block associated with a TU, the quantization module 106 can quantize the transform coefficients in the transform coefficient block. The quantization module 106 can quantize a transform coefficient block associated with a TU of a CU based on a QP value associated with the CU.

[0119] Video encoder 20 can associate a QP value with a CU in various ways. For example, video encoder 20 can perform rate skew analysis on a treeblock associated with CU. In rate skew analysis, the video encoder 20 can generate multiple encoded representations of the treeblock by performing an encoding operation multiple times on the treeblock. The video encoder 20 may associate different QP values with the CU when the video encoder 20 generates different encoded representations of the treeblock. The video encoder 20 may signal that a given QP value is associated with CU when the given QP value is associated with CU in an encoded representation of the treeblock that has a lower bit rate and distortion metric.

[0120] Inverse quantization module 108 and inverse transform module 110 can apply inverse quantization and inverse transforms on the transform coefficient block, respectively, to reconstruct a residual video block from the transform coefficient block. Reconstruction module 112 may add the reconstructed residual video block to corresponding samples from one or more predictive video blocks generated by prediction module 100 to produce a reconstructed video block associated with a TU. By reconstructing video blocks for each TU of a CU in this way, the video encoder 20 can reconstruct the video block of the CU.

[0121] After the rebuild module 112 reconstructs the video block of a CU, the filter module 113 can perform an unblock operation to reduce blocking artifacts in the video block associated with the CU. After performing one or more unlocking operations, filter module 113 may store the CU's reconstructed video block in decoded image buffer 114. Motion estimation module 122 and motion compensation module 124 may use a reference image. which contains the reconstructed video block to perform inter-prediction on PUs of subsequent images. Furthermore, the intra prediction module 126 can use video blocks reconstructed in decoded image buffer 114 to perform intra prediction on other PUs in the same image as the CU.

[0122] Entropy encoding module 116 may receive data from other functional components of video encoder 20. For example, entropy encoding module 116 may receive transform coefficient blocks from quantization module 106 and may receive syntax elements from the prediction module 100. When the entropy encoding module 116 receives the data, the entropy encoding module 116 may perform one or more entropy encoding operations to generate entropy-encoded data. For example, the video encoder 20 may perform a context-adaptive variable-length encoding (CAVLC) operation, a CABAC operation, a variable-to-variable-length (V2V) encoding operation, an Entropy-Division Entropy encoding operation. probability interval (PIPE), or other type of entropy encoding operation on the data. The entropy encoding module 116 may transmit a bit stream that includes the entropy encoded data.

[0123] As part of performing an entropy encoding operation on the data, the entropy encoding module 116 may select a context model. If the entropy encoding module 116 is performing a CABAC operation, the context model may indicate probability estimates of specific bins having specific values. In the context of CABAC, the term “bin” is used to refer to a bit of a binarized version of a syntax element.

[0124] Figure 3 is a block diagram illustrating an example video decoder 30 that is configured to implement the techniques of this disclosure. Figure 3 is provided for purposes of explanation and is not limiting on the techniques as amply exemplified and described in this disclosure. For purposes of explanation, this disclosure describes the video decoder 30 in the context of HEVC encoding. However, the techniques of this disclosure may be applicable to other encoding standards or methods.

[0125] In the example of figure 3, the video decoder 30 includes a plurality of functional components. The functional components of the video decoder 30 include an entropy decoding module 150, a prediction module 152, an inverse quantization module 154, an inverse transform module 156, a reconstruction module 158, a filter module 159, and a decoded image buffer 160. The prediction module 152 includes a motion compensation module 162 and an intraprediction module 164. In some examples, the video decoder 30 may perform a decoding pass generally reciprocal to the described coding pass. with respect to the video encoder 20 of Figure 2. In other examples, the video decoder 30 may include a higher number, a lower number or different functional components.

[0126] The video decoder 30 can receive a bit stream comprising encoded video data. The bit stream may include a plurality of syntax elements. When the video decoder 30 receives the bit stream, the entropy decoding module 150 can perform an analysis operation on the bit stream. As a result of performing the parsing operation on the bit stream, the entropy decoding module 150 can extract syntax elements from the bit stream. As part of performing the parsing operation, the entropy decoding module 150 may entropy decode entropy encoded syntax elements in the bit stream. The prediction module 152, inverse quantization module 154, inverse transform module 156, reconstruction module 158, and filter module 159 can perform a reconstruction operation that generates decoded video data based on the syntax elements extracted from the bit stream.

[0127] As discussed above, the bit stream may comprise a series of NAL units. Bitstream NAL units can include sequence parameter set NAL units, image parameter set NAL units, SEI NAL units, and so on. As part of performing the parsing operation on the bit stream, the entropy decoding module 150 may perform parsing operations that extract and entropy decode sets of sequence parameters from the NAL units of sequence parameters sets, sets of image parameter from image parameter set NAL units, SEI data from SEI NAL units, and so on.

[0128] In addition, bitstream NAL units may include encoded slice NAL units. As part of performing the parsing operation on the bit stream, the entropy decoding module 150 may perform parsing operations that extract and entropy decode encoded slices from the encoded slice NAL units. Each of the encoded slices can include a slice header and slice data. The slice header can contain syntax elements pertinent to a slice. Syntax elements in the slice header can include a syntax element that identifies a set of image parameters associated with an image that contains the slice. The entropy decoding module 150 can perform entropy decoding operations, such as CABAC decoding operations, on syntax elements in the encoded slice header to retrieve the slice header.

[0129] As part of extracting slice data from encoded slice NAL units, entropy decoding module 150 can perform parsing operations that extract syntax elements from CUs encoded in slice data. Extracted syntax elements can include syntax elements associated with transform coefficient blocks. The entropy decoding module 150 can then perform CABAC decoding operations on some of the syntax elements.

[0130] After the entropy decoding module 150 performs a parse operation on a non-partitioned CU, the video decoder 30 can perform a rebuild operation on the non-partitioned CU. To perform the rebuild operation on a non-partitioned CU, the video decoder 30 can perform a rebuild operation on each TU of the CU. By performing the reconstruction operation for each TU of the CU, the video decoder 30 can reconstruct a residual video block associated with the CU.

[0131] As part of performing a reconstruction operation on a TU, the inverse quantization module 154 can inverse quantize, that is, dequantize, a transform coefficient block associated with the TU. The inverse quantization module 154 can inverse quantize the transform coefficient block in a manner similar to the inverse quantization processes proposed by HEVC or defined by the H.264 decoding standard. the inverse quantization module 154 may use a quantization parameter QP calculated by the video encoder 20 for a CU of the transform coefficient block to determine a degree of quantization and similarly a degree of inverse quantization for the quantization module inverse 154 apply.

[0132] After the inverse quantization module 154 inverse quantizes a transform coefficient block, the inverse transform module 156 can generate a residual video block for the TU associated with the transform coefficient block. The inverse transform module 156 can apply an inverse transform to the transform coefficient block to generate the residual video block for the TU. For example, the inverse transform module 156 can apply an inverse DCT, an inverse integer transform, an inverse Karhunen-Loeve transform (KLT), an inverse rotation transform, an inverse directional transform, or other inverse transform to the block. of transform coefficient.

[0133] In some examples, the inverse transform module 156 may determine an inverse transform to apply to the transform coefficient block based on signaling from the video encoder 20. In such examples, the inverse transform module 156 may determine the inverse transform based on a signed transform at the root node of a quadtree to a treeblock associated with the transform coefficient block. In other examples, the inverse transform module 156 can infer the inverse transform of one or more encoding characteristics, such as block size, encoding mode, or the like. In some examples, the inverse transform module 156 may apply an inverse cascade transform.

[0134] If a CU PU was coded using Interprediction, motion compensation module 162 can generate a candidate list for the PU. In accordance with the techniques of that disclosure, the motion compensation module 162 can generate the candidate list for the PU such that each candidate in the candidate list that is generated based on motion information from at least one other PU is generated. without using transaction information from other PUs that belong to the same CU. The bit stream may include data that identifies a position of a selected candidate in the PU candidate list. After generating the candidate list for the PU, the motion compensation module 162 may generate a predictive video block for the PU based on one or more reference blocks indicated by the motion information of the PU. The PU reference blocks can be in different temporal images than the PU. Motion compensation module 162 can determine PU motion information based on motion information indicated by the candidate selected in the PU candidate list.

[0135] In some examples, motion compensation module 162 can refine a PU's predictive video block by performing interpolation based on interpolation filters. Identifiers for interpolation filters to be used for motion compensation with sub-sample precision can be included in the syntax elements. Motion compensation module 162 can use the same interpolation filters used by video encoder 20 during PU predictive video block generation to calculate interpolated values for sub-integer samples of a reference block. Motion compensation module 162 can determine the interpolation filters used by the video encoder 20 according to the received syntax information and use the interpolation filters to produce the predictive video block.

[0136] If a PU is encoded using intra prediction, the intra prediction module 164 can perform intra prediction to generate a predictive video block for the PU. For example, the intra prediction module 164 can determine an intra prediction mode for the PU based on syntax elements in the bit stream. The bit stream may include syntax elements that the intra prediction module 164 can use to determine the intra prediction mode of the PU.

[0137] In some cases, syntax elements may indicate that the intra prediction module 164 should use the intra prediction mode of another PU to determine the intra prediction mode of the current PU. For example, it may be likely that the intra prediction mode of the current PU is the same as the intra prediction mode of a neighboring PU. In other words, the intraprediction mode of the neighboring PU may be the most likely mode for the current PU. Consequently, in this example, the bit stream may include a small syntax element that indicates that the intra-prediction mode of the PU is the same as the intra-prediction mode of the neighboring PU. The intra prediction module 164 may then use the intra prediction mode to generate prediction data (e.g., predictive samples) for the PU based on video blocks from spatially neighboring PUs.

[0138] The reconstruction module 158 may use the residual video blocks associated with TUs of a CU and the predictive video blocks of the PUs of the CU, i.e. intra-prediction data or inter-prediction data, as applicable, to reconstruct the CU video block. Thereby, the video decoder 30 can generate a predictive video block and a residual video block based on syntax elements in the bitstream and can generate a video block based on the predictive video block and residual video block.

[0139] After the rebuild module 158 reconstructs the CU video block, the filter module 159 can perform an unlock operation to reduce CU-associated lock artifacts. After the filter module 159 performs an unblock operation to reduce blocking artifacts associated with the CU, the video decoder 30 can store the CU's video block in the decoded image buffer 160. The decoded image buffer 160 can provide images of reference for subsequent motion compensation, intra-prediction and presentation on a display device, such as display device 32 of Fig. 1. For example, video decoder 30 may perform, based on video blocks in decoded image buffer 160, intra-prediction or inter-prediction operations on the PUs of other CUs.

[0140] Fig. 4 is a conceptual diagram illustrating an example configuration of interprediction module 121. Interprediction module 121 can divide the current CU into PUs according to multiple division modes. For example, the interprediction module 121 can divide the current CU into PUs according to 2Nx2N, 2NxN, Nx2N and NxN division modes.

[0141] Interprediction module 121 can perform integer motion estimation (IME) and fractional motion estimation (FME) on each of the PUs. when the interprediction module 121 executes IME on a PU, the interprediction module 121 may fetch one or more reference images for a reference block for the PU. After finding a reference block for the PU, the interprediction module 121 can generate a motion vector that indicates, in integer precision, a spatial displacement between the PU and the reference block for the PU. When the interprediction module 121 executes FME on the PU, the interprediction module 121 can refine the motion vector generated by executing IME on the PU. A motion vector generated by running FME on a PU can be sub-integer precision (eg ^ pixel precision, M pixel precision, etc.). after generating a motion vector for the PU, the interprediction module 121 can use the motion vector for the PU to generate a block of predictive video for the PU.

[0142] In some examples where the interprediction module 121 generates the PU motion information using AMVP mode, the interprediction module 121 can generate a candidate list for the PU. The candidate list can include one or more candidates that are generated based on movement information from other PUs. for example, the candidate list may include original candidates that indicate movement information from other PUs and/or candidates that indicate movement information derived from movement information from one or more other PUs. after generating the candidate list for the PU, the interprediction module 121 can select a candidate from the candidate list and generate a motion vector difference (MVD) for the PU. The MVD for the PU can indicate a difference between a motion vector indicated by the selected candidate and the motion vector generated for the PU using IME and FME. In such examples, the interprediction module 121 may transmit a candidate index that identifies a location in the candidate list of the selected candidate. The interprediction module 121 can also transmit the MVD of the PU. Figure 6, described in detail below, illustrates an example AMVP operation.

[0143] In addition to generating movement information for the PUs by executing IME and FME on the PUs, the inter prediction module 121 can perform merge operations on each of the PUs. when the interprediction module 121 performs a merge operation on a PU, the interprediction module 121 can generate a candidate list for the PU. The list of candidates for the PU may include one or more original candidates. The original candidates in the candidate list may include one or more spatial candidates and a temporal candidate. Spatial candidates can indicate motion information from other PUs in the current image. The temporal candidate can be based on motion information from an installed PU of an image different from the current image. The temporal candidate can also be referred to as the temporal motion vector predictor (TMVP).

[0144] After generating the list of candidates, the interprediction module 121 can select one of the candidates from the list of candidates. The interprediction module 121 can then generate a predictive video block for the PU based on reference blocks indicated by the PU's motion information. In fusion mode, the PU movement information can be the same as the movement information indicated by the selected candidate. Figure 5, described below, is a flowchart illustrating an example merge operation.

[0145] After generating a predictive video block for the PU based on IME and FME and after generating a predictive video block for the PU based on a merge operation, the interprediction module 121 can select the video block generated by the FME operation or the predictive video block generated by the merge operation. In some examples, the interprediction module 121 may select a predictive video block for the PU based on a rate/distortion analysis of the predictive video block generated by the FME operation and the predictive video block generated by the merge operation.

[0146] After the interprediction module 121 has selected predictive video blocks for the PUs generated by splitting the current CU according to each of the split modes, the interprediction module 121 can select a partitioning mode for the current CU . In some examples, the interprediction module 121 may select a partitioning mode for the current CU based on a rate/distortion analysis of the selected predictive video blocks for the generated PUs by dividing the current CU according to each of the modes. of division. The interprediction module 121 can transmit the predictive video blocks associated with PUs belonging to the selected partitioning mode to the residual generation module 102. The interprediction module 121 can transmit syntax elements indicating the motion information of the PUs that belong to the partitioning mode selected for the entropy encoding module 116.

[0147] In the example of Figure 4, the inter prediction module 121 includes IME modules 180A-180N (collectively, “IME modules 180”), FME modules 182A-182N (collectively, “FME modules 182”), fusion modules 184A- 184N (collectively, 184 Fusion Modules), 186A-186N PU Mode Decision Modules (collectively, “186 PU Mode Decision Modules”), and a 188 CU Mode Decision Module.

[0148] IME modules 180, FME modules 182, and merge modules 184 can perform IME operations, FME operations, and merge operations on the PUs of the current CU. The example in Figure 4 illustrates the interprediction module 121 as including separate IME modules 180, FME modules 182, and merge modules 184 for each PU of each CU partitioning mode. In other examples, the interprediction module 121 does not include separate IME modules 180, FME modules 182, and merge modules 184 for each PU of each CU partitioning mode.

[0149] As illustrated in the example of Figure 4, IME module 180A, FME module 182A, and merge module 184A can perform an IME operation, an FME operation, and a merge operation on a PU generated by dividing the CU of according to a 2Nx2N partitioning mode. PU mode decision module 186A can select one of the predictive video blocks generated by IME module 180A, FME module 182A, and fusion module 184A.

[0150] IME module 180B, FME module 182B, and merge module 184B can perform an IME operation, an FME operation, and a merge operation on a left PU generated by dividing the CU according to an Nx2N partitioning mode. PU mode decision module 186B can select one of the predictive video blocks generated by IME module 180B, FME module 182B, and fusion module 184B.

[0151] IME module 180C, FME module 182C, and merge module 184C can perform an IME operation, an FME operation, and a merge operation on a right PU generated by CU division according to an Nx2N partitioning mode. PU mode decision module 186C can select one of the predictive video blocks generated by IME module 180C, FME module 182C, and fusion module 184C.

[0152] IME module 180N, FME module 182N, and merge module 184 can perform an IME operation, an FME operation, and a merge operation on a lower right PU generated by CU division according to an NxN partitioning mode. The PU mode decision module 186N can select one of the predictive video blocks generated by the IME module 180N, FME module 182N, and fusion module 184N.

[0153] After the PU 186 mode decision modules select predictive video blocks for the PUs of the current CU, the CU 188 mode decision module selects a partitioning mode for the current CU and transmits predictive video blocks and movement of PUs belonging to the selected partitioning mode.

[0154] Fig. 5 is a flowchart illustrating an example merge operation 200. A video encoder such as video encoder 20, can perform merge operation 200. In other examples, the video encoder can perform merge operations different from the merge operation 200. For example, in other examples, the video encoder may perform a merge operation in which the video encoder performs a greater number, a lesser number, or different steps than the merge operation 200. In In other examples, the video encoder may perform the merge operation steps 200 in different orders or in parallel. The encoder can also perform merge operation 200 on the coded PU in skip mode.

[0155] After the video encoder starts the merge operation 200, the video encoder can generate a candidate list for the current PU (202). The video encoder can generate the candidate list for the current PU in several ways. For example, the video encoder can generate the candidate list for the current PU according to one of the example techniques described below with respect to Figures 8-15.

[0156] As briefly discussed above, the candidate list for the current PU may include a temporal candidate. The temporal candidate can indicate the movement information of an installed PU. The installed PU can be spatially installed with the current PU, but it is in a reference image instead of the current image. This revelation can refer to the reference image that includes the installed PU as the relevant reference image. This revelation can refer to a reference image index of the relevant reference image as the relevant reference image index. As described above, the current image can be associated with one or more reference image lists, e.g. list 0, list 1, etc. A reference image index can indicate a reference image by indicating a position of the reference image in one of the reference image lists. In some examples, the current image can be associated with a list of combined reference images.

[0157] In some conventional video encoders, the relevant reference image index is the reference image index of a PU that covers a reference index source location associated with the current PU. In such conventional video encoders, the reference index source location associated with the current PU is immediately to the left of the current PU or immediately above the current PU. In this revelation, a PU can “cover” a specific location if the video block associated with the PU includes the specific location. In such conventional video encoders, the video encoder may use a reference image index of zero if the reference index source location is not available.

[0158] However, there may be cases where the reference index source location associated with the current PU is comprised in the current CU. In such cases, the PU covering the reference index source location associated with the current PU may be considered available if that PU is above or to the left of the current CU. However, the video encoder may need to access motion information from another PU of the current CU to determine the reference image containing the installed PU. Consequently, such conventional video encoders can use motion information (i.e., the reference image index) from a PU that belongs to the current CU to generate the temporal candidate for the current PU. In other words, such conventional video encoders can generate the temporal candidate using motion information from a PU that belongs to the current CU. Consequently, the video encoder may be unable to generate candidate lists for the current PU and the PU covering the reference index source location associated with the current PU in parallel.

[0159] According to the techniques of this disclosure, the video encoder can explicitly define, without reference to the reference image index of any other PU, the relevant reference image index. This can allow the video encoder to generate candidate lists for the current PU and other PUs of the current CU in parallel. As the video encoder explicitly sets the relevant reference image index, the relevant reference image index is not based on motion information from any other PU of the current CU. In some examples where the video encoder explicitly sets the relevant reference image index, the video encoder can always set the relevant reference image index to a fixed, predefined default reference image index to 0. In this way, the video encoder can generate a temporal candidate based on motion information from a PU installed in a reference frame indicated by a standard reference image index and can include the temporal candidate in the candidate list of the current CU.

[0160] In examples where the video encoder explicitly defines the relevant reference image index, the video encoder can explicitly flag the relevant reference image index in a syntax structure such as an image header, a slice header , an APS, or other syntax structure. In this example, the video encoder can flag the relevant reference image index for every LCU, CU, PU, TU or other sub-block type. For example, the video encoder may signal that the relevant reference image indices for each PU of a CU are equal to “1”.

[0161] In some examples, such as those described below with reference to Figures 9A-9F and 10A-F, the relevant reference image index may be set implicitly rather than explicitly. In such examples, the video encoder may generate each temporal candidate in the candidate lists for PUs of the current CU using movement information from PUs in reference images indicated by the reference image indices of PUs that cover locations outside the current CU, even if such locations are not strictly adjacent to the current PUs (ie, the PUs of the current CU).

[0162] After generating the candidate list for the current PU, the video encoder can generate predictive video block associated with the candidates in the candidate list (204). The video encoder can generate a predictive video block associated with a candidate by determining current PU motion information based on the nominated candidate's motion information and then generating the predictive video block based on one or more indicated reference blocks. by the current PU motion information. The video encoder can then select one of the candidates from the list of candidates (206). The video encoder can select the candidate in several ways. For example, the video encoder might select one of the candidates based on a skew/rate analysis on each of the predictive video blocks associated with the candidates.

[0163] After selecting the candidate, the video encoder can transmit a candidate index (208). The candidate index can indicate a position of the selected candidate in the candidate list. In some examples, the candidate index may be indicated as “merge_idx.”

[0164] Fig. 6 is a flowchart illustrating an example AMVP operation 210. A video encoder, such as a video encoder 20, can perform AMVP operation 210. Fig. 6 is merely an example of an AMVP operation.

[0165] After the video encoder starts AMVP operation 210, the video encoder can generate one or more motion vectors for a current PU (211). The video encoder can perform integer motion estimation and fractional motion estimation to generate the motion vectors for the current PU. As described above, the current image can be associated with two reference image lists, list 0 and list 1. If the current PU is predicted unidirectionally, the video encoder can generate either a list 0 motion vector or a motion vector from list 1 to the current PU. List 0 motion vector can indicate a spatial displacement between the current PU video block and a reference block in a reference image in list 0. List 1 motion vector can indicate a spatial displacement between the list 0 block of video of the current PU and a reference block in a reference image in list 1. If the current PU is bidirectionally predicted, the video encoder can generate a list 0 motion vector and a list 1 motion vector for the PU current.

[0166] After generating the motion vector or motion vectors for the current PU, the video encoder can generate a predictive video block for the current PU (212). The video encoder can generate the predictive video block for the current PU based on one or more reference blocks indicated by one or more motion vectors for the current PU.

[0167] In addition, the video encoder can generate a candidate list for the current PU (213). Each candidate in the candidate list that is generated based on movement information from at least one other PU is generated without using movement information from any other PU that belongs to the current CU. The video encoder can generate the candidate list for the current PU in several ways. For example, the video encoder can generate the candidate list for the current PU according to one or more of the example techniques described below with respect to Figures 8-15. In some examples, when the video encoder generates the candidate list in AMVP 210 operation, the candidate list may be limited to two candidates. In contrast, when the video encoder generates the candidate list in a merge operation, the candidate list can include more candidates (for example, five candidates).

[0168] After generating the candidate list for the current PU, the video encoder can generate one or more motion vector differences (MVDs) for each candidate in the candidate list (214). The video encoder can generate a motion vector difference for a candidate by determining a difference between a motion vector indicated by the candidate and a corresponding motion vector of the current PU.

[0169] If the current PU is predicted unidirectionally, the video encoder can generate a unique MVD for each candidate. If the current PU is predicted bidirectionally, the video encoder can generate two MVDs for each candidate. The first MVD can indicate a difference between a candidate motion vector and the current PU list 0 motion vector. The second MVD can indicate a difference between a candidate motion vector and the list 1 motion vector of the current PU.

[0170] The video encoder can select one or more of the candidates from the list of candidates (215). The video encoder can select one or more candidates in several ways. For example, the video encoder might select one of the candidates based on the number of bits required to represent motion vector differences for the candidates.

[0171] After selecting one or more candidates, the video encoder may transmit one or more reference image indices for the current PU, one or more candidate indices, and one or more motion vector differences for one or more candidates selected (216).

[0172] In cases where the current image is associated with two reference image lists, list 0 and list 1, and the current PU is predicted unidirectionally, the video encoder can transmit a reference image index for list 0 ( “ref_idx_10”) or list 1 (“ref_idx_11”). The video encoder can also transmit a candidate index ("mvp_10_flag") that indicates a position in the candidate list of the selected candidate for the current PU list 0 motion vector. Alternatively, the video encoder may transmit a candidate index ("mvp_11_flag") that indicates a position in the candidate list of the selected candidate for the current PU list 1 motion vector. The video encoder can also stream the MVD for list 0 motion vector or list 1 motion vector of current PU.

[0173] In cases where the current image is associated with two reference image lists, list 0 and list 1, and the current PU is bidirectionally predicted, the video encoder can transmit a reference image index for list 0 ( “ref_idx_10”) and a reference image index for list 1 (“ref_idx_11”). The video encoder may also transmit a candidate index ("mvp__10_flag") that indicates a position in the candidate list of the selected candidate for the list 0 motion vector of the current PU. In addition, the video encoder can transmit a candidate index ("mvp_11_flag") that indicates a position in the candidate list of the selected candidate for the current PU list 1 motion vector. The video encoder can also transmit the MVD for the list 0 motion vector of the current PU and the MVD for the list 1 motion vector of the current PU.

[0174] Fig. 7 is a flowchart illustrating an example motion compensation operation 220 performed by a video decoder such as video decoder 30. Fig. 7 is merely an example motion compensation operation.

[0175] When the video decoder performs motion compensation operation 220, the video decoder may receive an indication of a candidate selected for the current PU (222). For example, the video decoder can receive a candidate index that indicates a position of the selected candidate in a candidate list of the current PU.

[0176] If the current PU motion information is encoded using AMVP mode and the current PU is predicted bi-directionally, the video decoder can receive a first candidate index and a second candidate index. The first candidate index indicates a position in the candidate list of a candidate selected for a list 0 motion vector of the current PU. The second candidate index indicates a position in the candidate list of a candidate selected for a list 1 motion vector of the current PU.

[0177] In addition, the video decoder can generate a candidate list for the current PU (224). According to the techniques of this disclosure, the video decoder can generate the candidate list such that each candidate in the candidate list that is generated based on motion information from at least one other PU is generated without using motion information from any other PU that belongs to the current CU. The video decoder can generate such a candidate list for the current PU in various ways. For example, the video decoder can use the techniques described below with reference to Figures 8-15 to generate the candidate list for the current PU. When the video decoder generates a temporal candidate for the candidate list, the video decoder can explicitly or implicitly set the reference image index that identifies the reference image that includes the installed PU, as described above with respect to Figure 5 .

[0178] In some examples, a video encoder, such as a video encoder or a video decoder, can adapt the candidate list size to a CU based on PU size, PU format, PU index, information about neighboring video blocks, and/or other information. Information about neighboring video blocks may include prediction modes of neighboring video blocks, motion vectors of neighboring video blocks, motion vector differences of neighboring video blocks, reference image indices of video blocks neighbors, prediction directions of neighboring video blocks, transform coefficients of neighboring video blocks, and/or other information about neighboring video blocks. For example, for the one CU with 2NxN mode, the original candidate for the second PU that is located inside the first PU can be removed from the candidate list. As a result, in this case, the size of the candidate list for the second PU may be smaller than the size of the candidate list for the first PU.

[0179] In some examples, the video encoder may adapt the order of candidate lists for PUs based on PU size, PU format, PU index, information about neighboring video blocks, and/or other information. Information about neighboring video blocks may include prediction modes of neighboring video blocks, motion vectors of neighboring video blocks, motion vector differences of neighboring video blocks, reference image indices of neighboring video blocks, prediction directions of neighboring video blocks, transform coefficients of neighboring video blocks, and/or other information about neighboring video blocks. For example, when a merge candidate list is generated based on movement information from PUs outside the current CU, the order of candidates in the candidate list can be adjusted for each PU. For those candidates that are located further from the PU, their order in the list may be lowered relative to those that are closer to the PU. As a result, although the same set of candidates is used to form a candidate list for each PU, the order of candidates on the list may be different for each PU in the CU due to different PU locations for those candidates.

[0180] After generating the candidate list for the current PU, the video decoder can determine the motion information of the current PU based on motion information indicated by the one or more candidates selected in the candidate list for the current PU (225 ). For example, if the current PU's movement information is encoded using the merge mode, the current PU's movement information can be the same as the movement information indicated by the selected candidate. If the current PU motion information is encoded using AMVP mode, the video decoder can use one or more motion vectors indicated by the selected candidate or candidates and one or more MVDs indicated in the bitstream to reconstruct a motion vector or vectors. current PU motion. The reference image index(es) and prediction direction indicator(s) of the current PU may be the same as the reference image index(es) and prediction direction indicator(s) of a or more selected candidates.

[0181] After determining the current PU motion information, the video decoder can generate a predictive video block for the current PU based on one or more reference blocks indicated by the current PU motion information (226).

[0182] In Figure 8A and 8B, all PUs of a CU share a single list of fusion candidates, which can be identical to the list of fusion candidates of a 2Nx2N PU. thus, in Figures 8A and 8B, a video encoder can generate a list of merge candidates shared by all PUs of the current CU. In this way, the current CU can be partitioned into the plurality of PUs according to a selected partitioning mode (e.g. 2NxN, Nx2N, NxN, etc.) other than a 2Nx2N partitioning mode and the movement information of each of the PUs are determinable based on movement information indicated by a candidate selected from the merge candidate list. The video encoder can generate the shared merge list for the plurality of PUs in the same way as if the CU were partitioned in a 2Nx2N mode. in other words, the merge candidate list is the same as a candidate list that would be generated if the current CU had been partitioned according to the 2Nx2N partitioning mode. an advantage of such a scheme may be that for each CU, regardless of how many PUs the CU has, only one merge list can be generated. Additionally, based on such a scheme, motion estimation for different PUs in the same CU can be done in parallel. In this example, the merge list that is shared by all PUs on the same CU can be done in parallel. In this example, the merge list that is shared by all PUs of the CU can be generated in the same way as if the CU were partitioned according to a 2Nx2N partitioning mode. Figures 8A and 8B are examples in which a list of merge candidates is generated without using movement information from PUs of the current CU and the same list of merge candidates is shared by all PUs of the current CU.

[0183] Figure 8A is a conceptual diagram illustrating a CU 250 and example 252A-E source locations associated with CU 250. This disclosure may refer to 252A-252E source locations collectively as 252 source locations. Home location 252A is located to the left of CU 250. Home location 252B is located above CU 250. Home location 252C is located to the upper-right of CU 250. Home location 252D is located to the lower left of the CU 250. The home location 252E is located on the left above the CU 250. Each of the home locations 252 is outside the CU 250.

[0184] The CU 250 can include one or more PUs. a video encoder can generate motion candidates for each CU 250 PU based on motion information from PUs covering source locations 252. In this way, the video encoder can generate candidate lists for the CU 250 PUs of such that each candidate that is generated based on movement information from at least one other PU is generated without using the movement information from any other PUs that belong to CU 250. The generation of candidate lists for CU 250 PUs of that mode can allow the video encoder to generate candidate lists from multiple CU 250 PUs in parallel.

[0185] Figure 8B is a conceptual diagram illustrating a CU 260 and example 262A-G source locations associated with CU 260. This disclosure may refer to 262A-G source locations collectively as 262 source locations. The example of figure 8B is similar to the example of figure 8A, except that the CU 260 is associated with seven home locations instead of five home locations as shown in figure 8A. In the example of Figure 8B, the video encoder can generate candidate lists for each PU of CU 260 based on motion information from one or more PUs covering source locations 262.

[0186] Figure 9A is a conceptual diagram illustrating example reference index source locations on the left of a 2NxN partitioned CU 300. PU 302 and PU 304 belong to CU 300. In the example of Figure 9A, the location of Reference index source 306 is associated with PU 302. Reference index source location 308 is associated with PU 304.

[0187] Figure 9B is a conceptual diagram illustrating example reference index source locations on the left of a CU Nx2N 340. PU 342 and PU 344 belong to CU 340. In the example of Figure 9B, the source location reference index 348 is associated with both PU 342 and PU 344.

[0188] Figure 9C is a conceptual diagram illustrating above example reference index source locations of a 2NxN partitioned CU 320. PU 322 and PU 324 belong to CU 320. In the example of Figure 9C, the location of reference index source 328 is associated with PU 322 and PU 324.

[0189] Figure 9D is a conceptual diagram illustrating above example reference index origin locations of a CU Nx2N 360. PU 362 and PU 364 belong to CU 360. In the example of Figure 9D, the origin location index 366 is associated with PU 362. The source location of reference index 368 is associated with PU 364.

[0190] Figure 9E is a conceptual diagram illustrating example reference index source locations to the left of an example NxN partitioned CU 400. CU 400 is partitioned into PUs 402, 404, 406, and 408. Reference index source 410 is associated with PUs 402 and 404. Reference index source location 412 is associated with PUs 406 and 408.

[0191] Figure 9F is a conceptual diagram illustrating example reference index source locations above an NxN partitioned CU 420. The CU 420 is partitioned into PUs 422, 424, 426, and 428. The index source location reference index 430 is associated with PUs 422 and 426. Reference index source location 432 is associated with PUs 426 and 428.

[0192] As illustrated in the examples of Figures 9A-9F, if the original reference index source location associated with the current PU is comprised of the current CU, the video encoder may, according to the techniques of that disclosure and instead of use the original reference index source location, identify a location outside the current CU that corresponds to the original reference index source location associated with the current PU. A location outside the current CU may match the original reference index source location within the current CU based on the criteria that the locations are spatially situated relative to the current PU in the same way (e.g. both are bottom left, left , above-left, above, or above-right of the current PU). The video encoder can infer that the relevant reference image index is equal to a reference image index of a PU that covers the corresponding location outside the current CU. In this way, the video encoder can determine the relevant reference image index without using motion information from any other PUs within the current CU.

[0193] As illustrated in the example of Fig. 9C, a location 326 immediately above the PU 324 is within the CU 320. Instead of using the PU reference image index covering the location 326, the video encoder may use the PU reference image index covering a corresponding location outside the CU 320 (i.e., reference index source location 328). Similarly, in the example in Fig. 9B, a location 346 immediately to the left of PU 344 is within CU 340. Instead of using the PU reference image index covering location 346, the video encoder may use PU reference image that covers a corresponding location outside the CU 340 (i.e., reference index source location 348). In some examples, the corresponding locations outside the current CU are spatially situated with respect to the current PU in the same way as the original locations that are inside the current CU.

[0194] Thus, in response to the determination that a reference index source location associated with the current PU is within the current CU, the video encoder can identify a corresponding location outside the current CU. The video encoder can then generate a temporal candidate based on motion information from a PU installed in a reference image indicated by a PU covering the corresponding location outside the current CU. The video encoder can then add the temporal candidate to the candidate list for the current CU.

[0195] Figure 10A is a conceptual diagram illustrating an example reference index origin location on the left of a 2NxN partitioned CU 500. PU 502 and PU 504 belong to CU 500. Figure 10B is a conceptual diagram illustrating an example reference index source location on the left of an Nx2N partitioned CU 520. PU 522 and PU 524 belong to CU 520. Fig. 10C is a conceptual diagram illustrating a reference index source location above example of a 2NxN partitioned CU 540. PU 542 and PU 544 belong to CU 540. Figure 10D is a conceptual diagram illustrating an example reference index source location above an Nx2N partitioned CU 560. PU 562 and PU 564 belong to CU 560. Figure 10E is a conceptual diagram illustrating an example reference index source location on the left of an NxN partitioned CU 580. CU 580 is partitioned into PUs 582, 584, 586 and 588. Figure 10F is a conceptual diagram illustrating an example reference index source location above an NxN 600 partitioned CU. The CU 600 is partitioned into PUs 602, 604, 606, and 608.

[0196] Figures 10A-10F are similar to Figures 9A-9F in that the video encoder can be configured to determine the relevant reference image index for the current PU from a PU covering an index source location reference associated with the current PU. However, unlike the examples in Figures 9A-9F, each PU of a CU is associated with the same reference index origin location. In other words, the reference image index for all PUs in the CU can be derived from a single neighboring block outside the CU.

[0197] For example, in the example of Figure 10A, both PU 502 and 504 are associated with a reference index origin location 506 that is to the left of the CU 500. In contrast, in the example of Figure 9A, the PU 302 and 304 are associated with reference index origin locations 306 and 308. Similarly, in the example of Fig. 10D, both PU 562 and PU 564 are associated with a single reference index origin location 566 that is above CU 560. In the example of Figure 10E, PUs 582, 584, 586, and 588 are associated with a single reference index source location 590 which is located to the left of CU 580. In the example of Figure 10F, PUs 602, 604, 606 and 608 are associated with a single reference index source location 610 which is located above the CU 600.

[0198] In other examples, the video encoder may determine the temporal candidate reference image indices of each PU of a CU from any other PU that is spatially located outside the CU. For example, the video encoder can determine the temporal candidate reference image indices of each PU of a CU from a PU that is located left, located above, located above and left, located above and right, or located below and to the left of the CU. The use of a single or multiple source locations outside the current CU to encode information within the current CU can be applied to current CU or blocks of other types or at different levels.

[0199] Figure 11 is a flowchart illustrating an example operation 700 to generate a temporal candidate for a PU. A video encoder, such as video encoder 20 or video decoder 30, can perform operation 700. Fig. 11 is merely an example of an operation for generating a temporal candidate for a PU.

[0200] After the video encoder starts operation 700, the video encoder can determine if a PU covering the reference index source location associated with the current PU is available (702). This revelation can refer to the PU covering the reference index source location as the reference index source PU. The PU benchmark source may be unavailable for various reasons. For example, the PU benchmark source might be unavailable if the PU benchmark source is not in the current image. In another example, the PU benchmark source may be unavailable if the PU benchmark source is intrapredicted. In another example, the PU benchmark source may be unavailable if the PU benchmark source is in a different slice than the current PU.

[0201] In response to the determination that the reference index source PU for the current PU is available (“YES” of 702), the video encoder may generate a temporal candidate that indicates the motion information of an installed PU in a reference image indicated by the reference image index of the reference index source PU (704). For example, in the example of Fig. 9C, the PU covering the location 328 may be the reference index source PU for the PU 324. In that case, the video encoder may generate a temporal candidate for the PU 324 that indicates the motion information from a PU installed in a reference image indicated by the reference image index of the PU covering location 328.

[0202] In response to the determination that the reference index source PU for the current PU is not available (“NO” of 702), the video encoder may look for an available PU among the PUs that are spatially neighboring the CU current (706). If the video encoder does not find an available PU (“NO” of 708), the video encoder can generate a temporal candidate that indicates the motion information of a PU installed in a reference image indicated by a reference image index. default (710). For example, if the video encoder does not find an available PU, the video encoder can generate a temporal candidate for the current PU from a PU installed in a reference image indicated by a reference image index of 0, 1, or another number that is selected by default.

[0203] On the other hand, if the video encoder finds an available PU (“YES” of 708), the video encoder can generate a temporal candidate that indicates the motion information of a PU installed in a reference image indicated by an available PU reference image index (712). For example, if the available PU reference image index is equal to 1, the video encoder can generate a temporal candidate that indicates the motion information of a PU installed in a reference image indicated by reference image index 1 .

[0204] In another example, if the reference index source PU is unavailable, the video encoder can generate the temporal candidate that indicates the motion information of a PU installed in a reference image indicated by an image index standard reference. In this example, the default reference image index can be a default value (for example, zero) or it can be flagged in an image parameter set, a slice header, an APS, or other syntax structure.

[0205] Thus, in the example of figure 11, the video encoder can, in response to the determination that a reference index source PU is not available, search for an available PU that is spatially neighboring the current CU. The video encoder can then generate a temporal candidate based on motion information from a PU installed in a reference image indicated by an available PU reference image index. The video encoder can include the temporal candidate in the candidate list for the current PU.

[0206] Figure 12 is a flowchart illustrating an example operation 800 to generate a candidate list for a PU. A video encoder such as video encoder 20 or video decoder 30 can perform operation 800. Fig. 12 is merely an example of an operation for generating a candidate list for a pU.

[0207] After the video encoder starts operation 800, the video encoder can generate spatial candidates based on motion information from PUs that are spatially neighbors of the current PU and outside the current CU (802). In this way, candidates who are in the current CU are excluded from the candidate list. For example, for an upper-right PU of an NxN partitioned CU, a left candidate (L) and a lower left candidate (BL) are excluded from their candidate list. For a lower left PU of an NxN partitioned CU, the above candidate (A) and the above right candidate (RA) are excluded from the candidate list. For a right-bottom PU of an NxN partitioned CU, three candidates including the left candidate (L), the top candidate (A), and the top left candidate (LA) are excluded from the candidate list.

[0208] The video encoder can then add the spatial candidates to the candidate list for the current PU (804). Furthermore, the video encoder can generate a temporal candidate that indicates motion information from a PU installed in a reference image (806). The video encoder can then add the temporal candidate to the candidate list for the current PU (808).

[0209] Video encoder can perform 800 operation when current PU motion information is signaled in merge mode. The video encoder can also perform 800 operation or similar operation when current PU motion information is signaled in AMVP mode. In the examples where the current CU is flagged in AMVP mode, candidates in the candidate list can be AMPV candidates.

[0210] In this way, the video encoder can generate spatial candidates based on motion information from PUs that are spatially neighbors of a current PU and outside the current CU. The video encoder can then add the spatial candidates to the candidate list for the current PU.

[0211] Figure 13 is a flowchart illustrating an example operation 850 to generate a candidate list for a PU. A video encoder such as a video encoder 20 or video decoder 30 can perform operation 850. Fig. 13 is merely an example of an operation for generating a candidate list for a PU.

[0212] After the video encoder starts 850 operation, the video encoder can generate spatial candidates for the current PU based on motion information from PUs that are spatial neighbors of the current CU (852). The video encoder can then add the spatial candidates to the candidate list for the current PU (854). In the example in Figure 13, the video encoder can replace spatial candidate source locations that are neighbors of the current PU but are in the current CU with corresponding spatial candidate source locations that are outside the current CU. In this way, the locations used by the video encoder in Figure 13 to generate the spatial candidates are moved to (ie, replaced with) corresponding locations outside the current CU. Corresponding locations outside the current CU can be located in any neighboring block position: left, above, above left, above right, below left in relation to the current CU. Thus, instead of removing dependent candidates from the candidate list as described above with respect to Figure 12, candidates can be taken from neighboring CUs located outside the current CU. As described below, Figures 14A, 14B, 15A, 15B, 15C and 15D illustrate spatial candidate source locations used by the video encoder in accordance with operation 850 to generate spatial candidates.

[0213] In some examples, if a spatial candidate origin location that is neighboring the current PU is not comprised in the current CU and the corresponding PU (i.e., the PU covering the spatial candidate origin location) is unavailable , the video encoder can perform a search process among neighboring PUs to find an available PU. If the video encoder is able to find an available PU, the video encoder can generate a spatial candidate based on the motion information of the available PU. Alternatively, if a spatial candidate source location that is a neighbor of the current PU is not comprised in the current CU and the corresponding PU (i.e., the PU covering the spatial candidate source location) is unavailable, the video encoder can generate a spatial candidate that has a default value, such as zero. The default value can be flagged in a PPS, a slice header, an APS, or another type of header.

[0214] In addition, the video encoder can generate a temporal candidate for the current PU (856). The video encoder can then add the temporal candidate to the candidate list for the current PU (858).

[0215] Video encoder can perform 850 operation when current PU motion information is signaled in merge mode. The video encoder can also perform 850 operation or similar operation when current PU motion information is signaled in AMVP mode. In the examples where the current CU is flagged in AMVP mode, candidates in the candidate list can be AMVP candidates.

[0216] In the example in Figure 13, a set of spatial candidate origin locations for the current CU may initially include a first spatial candidate origin location that is below and to the left of the current PU, a second candidate origin location spatial candidate origin location that is to the left of the current PU, a third spatial candidate origin location that is above-left of the current PU, a fourth spatial candidate origin location that is above the current PU, and a fifth spatial candidate origin location which is above-right of the current PU. The video encoder may replace any of the spatial candidate source locations that are comprised in the current CU with corresponding spatial candidate source locations outside the current CU. The video encoder can then generate spatial candidates based on motion information from PUs that cover the spatial candidate source locations and include the spatial candidates in the candidate list for the current pU.

[0217] Fig. 14A is a conceptual diagram illustrating example spatial candidate source locations associated with a right PU of an example Nx2N partitioned CU 900. PU 902 and PU 904 belong to CU 900. The video encoder may generate spatial candidates for PU 904 based on motion information from PUs covering spatial candidate origin locations 906, 908, 910, 914, and 918. Spatial candidate origin location 906 is located to the left-above of PU 904 Spatial candidate origin location 908 is located above PU 904. Spatial candidate origin location 910 is located to the right above PU 904. Spatial candidate origin location 914 is located below-left of PU 904. Location 916 is spatially located to the left of PU 904. However, instead of using motion information from the PU covering location 916 (i.e., PU 902) to generate a spatial candidate for PU 904, the video can use motion information from a PU covering spatial candidate source location 918 to generate a spatial candidate for PU 904. Spatial candidate source location 918 is especially to the left of CU 900.

[0218] Fig. 14B is a conceptual diagram illustrating example spatial candidate source locations associated with a lower PU of a 2NxN split CU 920. PU 922 and PU 924 belong to CU 920. The video encoder may generate candidates to PU 922 based on spatial candidate source locations that are spatially left-up, up, right-up, left, and down-left from PU 922. Due to the position of PU 922 on CU 920, none of these locations of candidate spatial origin is comprised in the CU 920. Consequently, there is no need for the video encoder to “move” any of the spatial candidate origin locations associated with the PU 922 to generate spatial candidates for the PU 922 that are based on motion information from the PU 922. PUs outside the CU 920.

[0219] The video encoder can generate spatial candidates for PU 924 based on spatial candidate source locations 926, 928, 932, 934, and 936. Spatial candidate source location 928 is located above right of PU 924. Spatial candidate source location 932 is spatially located below left of PU 924. Spatial candidate source location 934 is spatially located to left of PU 924. Spatial candidate source location 936 is spatially located above left PU 924.

[0220] Location 938 is spatially located above PU 924. However, location 938 is located on CU 920. Therefore, instead of using the PU motion information covering location 938 (i.e. PU 922) to generate a spatial motion candidate for the PU 924, the video encoder may generate a spatial motion candidate for the PU 924 based on motion information from a PU covering the spatial candidate source location 926.

[0221] Figures 15A-15D are conceptual diagrams illustrating spatial candidate source locations associated with PUs of a partitioned NxN 950 CU. PUs 952, 954, 956 and 958 belong to CU 950. Figure 15A is a conceptual diagram illustrating example spatial candidate source locations associated with PU 952. As illustrated in the example of Fig. 15A, the video encoder can generate spatial motion candidates for PU 952 based on motion information from PUs covering source locations candidate spatial locations 960, 962, 964, 966, and 968. None of the spatial candidate source locations 960, 962, 964, 966, or 968 are located on the CU 950. Therefore, there is no need for the video encoder to “move” any of the spatial candidate source locations associated with PU 952 to generate a motion candidate for PU 952.

[0222] Figure 15B is a conceptual diagram illustrating example spatial candidate source locations associated with PU 954. As illustrated in the example of Figure 15B, the video encoder can generate spatial motion candidates for PU 954 based on the motion information from PUs covering spatial candidate source locations 980, 982, 984, 986, and 988. Spatial candidate source locations 980, 982, and 984 are located outside CU 950. Location 990 is spatially to the left of the PU 954. Location 992 is spatially below-left of PU 954. However, locations 990 and 992 are within CU 950. Consequently, instead of generating spatial motion candidates based on motion information from PUs covering locations 990 and 992 (i.e., PUs 952 and 956) the video encoder can generate spatial motion candidates for the PU 954 based on motion information from PUs that cover corresponding locations outside the CU 950 (i.e., locations of and origin of space candidate 986 and 988). Spatial candidate origin locations 986 and 988 are outside PU 950.

[0223] Fig. 15C is a conceptual diagram illustrating example spatial candidate source locations associated with PU 956. As illustrated in the example of Fig. 15C, the video encoder can generate spatial motion candidates for PU 956 based on the PU movement information covering spatial candidate source locations 1000, 1002, 1004, 1006, and 1008. Spatial candidate source locations 1000, 1002, 1004, 1006, and 1008 are locations outside of CU 950. Location 1010 is spatially above PU 956. Location 1012 is spatially above-right of PU 956. However, locations 1010 and 1012 are within CU 950. Consequently, instead of generating spatial motion candidates based on motion information from the PUs they cover locations 990 and 992 (i.e. PUs 952 and 954), the video encoder can generate spatial motion candidates for PU 954 based on motion information from PUs covering corresponding locations. tes outside CU 950 (that is, spatial candidate source locations 1000 and 1002).

[0224] Figure 15D is a conceptual diagram illustrating example spatial candidate source locations associated with the PU 958. As illustrated in the example of Figure 15D, the video encoder can generate spatial motion candidates based on motion information from the PUs that cover spatial candidate source locations 1020, 1022, 1024, 1026, and 1028. Spatial candidate source locations 1020, 1022, 1024, 1026, and 1028 are locations outside of CU 950. Location 1030 is spatially above PU 956 Location 1032 is spatially above-left PU 956. Location 034 is spatially left of PU 958. However, locations 1030, 1032 and 1034 are on CU 950. Consequently, instead of generating spatial motion candidates based on motion information from the PUs covering locations 1030, 1032, and 1034 (i.e., PUs 954, 952, and 956), the video encoder can generate spatial motion candidates for the PU 954 based on the motion information from the PUs that cover corresponding locations outside the CU 950 (i.e., spatial candidate source locations 1020, 1028, and 1026).

[0225] Figures 14A, 14B, and 15A-15D show CUs partitioned according to Nx2N, 2NxN, and NxN division modes. However, similar concepts can be applied with respect to other division modes.

[0226] In one or more examples, the functions described may be implemented in hardware, software, firmware or any combination thereof. If implemented in software, functions can be stored or transmitted as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer readable media may include computer readable storage media, which is a tangible medium such as data storage media, or communication media including any medium that facilitates the transfer of a computer program from one place to another, by example, according to a communication protocol. Thus, computer-readable media generically may correspond to (1) tangible computer-readable storage media that are non-transient or (2) a communication medium such as a signal or carrier wave. Data storage media can be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementing the techniques described in this disclosure. A computer program product may include computer readable medium.

[0227] By way of example, and not limitation, such computer readable storage media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage devices, flash memory, or any other means that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Furthermore, any connection is aptly termed a computer readable medium. For example, if instructions are transmitted from a website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio and microwave, so coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. It should be understood, however, that computer-readable storage media and data storage media do not include connections, carrier waves, signals, or other transient media, but are instead addressed to tangible, non-transient storage media. Disk and disc, as used here, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disc, and Blu-ray disc, where disks typically reproduce data magnetically while discs reproduce data optically with lasers. Combinations of the above must also be included in the scope of computer readable media.

[0228] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable logic arrays (FPGAs), or other equivalent discrete or integrated logic circuitry. Accordingly, the term "processor" as used herein may refer to any of the above structure or any other structure suitable for implementing the techniques described herein. Additionally, in some respects, the functionality described here may be provided in dedicated hardware and/or software modules configured to encode and decode, or incorporated into a combined codec. Furthermore, the techniques could be fully implemented in one or more circuits or logic elements.

[0229] The techniques of this disclosure can be implemented in a wide variety of devices or apparatus, including a cordless telephone set, an integrated circuit (IC), or a set of ICs (eg, a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, multiple units may be combined into one codec hardware unit or provided by a collection of interoperable hardware units, including one or more processors as described above, in combination with appropriate software and/or firmware.

[0230] Several examples have been described. These and other examples fall within the scope of the claims that follow.

Claims (6)

1. Method (220) for decoding video data, the method comprising, for a plurality of prediction units, PUs, which belong to a current encoding unit, CU,: generating a candidate set of CU motion by using neighboring PUs outside the current CU, the PUs used to generate the candidate move set consisting of neighboring PUs to the left of the current CU, above the current CU, above and to the right of the current CU, below and to the left of the current CU, and above and to the left of the current CU; determining (225), based at least in part on the movement information (222) indicated by the candidate selected for the PU, the movement information of the PU; and generating (226), based at least in part on a reference block indicated by the PU motion information, a predictive video block for the PU; the method characterized in that it comprises: for each prediction unit (PU) in a plurality of PUs, selecting (224) a fusion mode or an advanced motion vector prediction mode, AMVP, candidate for the PU only when select a candidate from the candidate pool so that the selected candidate is generated without using movement information from any other PU belonging to the current CU. 2. Method, according to claim 1, characterized in that it additionally comprises: identifying the PU reference block based on a motion vector indicated by the candidate selected for the PU; and generate a reconstructed video block for the current CU based on the PUs' predictive video blocks. 3. Video decoding device for decoding video data comprising a plurality of prediction units, PUs belonging to an encoding unit, actual CU (30) comprising: mechanisms for generating a candidate set of CU motion when using PUs neighbors outside the current CU, the PUs used to generate the candidate move set consisting of neighbor PUs to the left of the current CU, above the current CU, above and to the right of the current CU, below and to the left of the current CU and above, and the left of current CU; mechanisms for determining, based at least in part on the movement information indicated by the candidate selected for the PU, the movement information of the PU; and mechanisms for generating, for each PU belonging to the current CU and based at least in part on a reference block indicated by the PU's motion information, a predictive video block for the PU; the device characterized in that it comprises: mechanisms for selecting, for each prediction unit (PU) in a plurality of PUs that belong to an encoding unit, CU, current, a merge mode or a prediction vector mode of advanced move, AMVP, candidate for the PU only by selecting a candidate from the candidate pool so that the selected candidate is generated without using move information from any other PU belonging to the current CU. 4. Method (200, 210) for encoding video data, the method comprising, for a plurality of prediction units (PUs) belonging to an encoding unit, current CU: generating a candidate motion set of CUs using PUs neighbors outside the current CU, the PUs used to generate the candidate move set consisting of neighbor PUs to the left of the current CU, above the current CU, above and to the right of the current CU, below and to the left of the current CU and above, and the left of current CU; generating (204, 212), based at least in part on a reference block indicated by the motion information of the selected candidate for the PU, a block of predictive video for the PU; the method characterized in that it additionally comprises: for each PU in the plurality of PUs, selecting (202, 213) a fusion mode or an advanced motion vector prediction mode, AMVP, candidate for the PU only when selecting a candidate from the candidate set so that the selected candidate is generated without using movement information from any other PU belonging to the current CU. 5. Video encoding device (20) for encoding video data comprising a plurality of prediction units, PUs, belonging to a current encoding unit, CU, comprising: mechanisms for generating a candidate set of CU motion when using neighbor PUs outside the current CU, the PUs used to generate the candidate move set consisting of neighbor PUs to the left of the current CU, above the current CU, above and to the right of the current CU, below and to the left of the current CU, and above and to the left of the current CU; mechanisms for generating, for each PU belonging to the current CU and based at least in part on a reference block indicated by the motion information of the selected candidate for the PU, a predictive video block for the PU; the device characterized in that it additionally comprises: mechanisms for selecting, for each prediction unit, PU, in the plurality of PUs, a fusion mode or an advanced motion vector prediction mode, AMVP, candidate for the PU only when select a candidate from the candidate pool so that the selected candidate is generated without using movement information from any other PU belonging to the current CU. 6. Computer readable memory characterized in that it comprises instructions stored therein which, when executed, configure one or more processors to execute the method as defined in any one of claims 1, 2 and 4.

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